Publikationen zum Thema Spiroergometrie.

Beneficial metabolic and cardiovascular effects of anthocyanin-rich New Zealand blackcurrant (NZBC) were primarily observed in studies with female and male Caucasian participants. We examined the effects of 14-day intake of NZBC extract (daily 210 mg of anthocyanins) during supine rest and moderate-intensity treadmill walking in Southeast Asian women (n = 16, age: 23 ± 5 years, BMI: 22.9 ± 3.8 kg·m− 2, body fat (BF): 35 ± 5%). A randomized, double-blind, placebo-controlled, cross-over design was used. Beat-by-beat (PhysioFlow® Endure™) and breath-by-breath (Cortex Metalyzer 3B) measurements were recorded during 10-min of supine rest and 30-min of moderate-intensity treadmill walking (speed: 4.84 ± 1.00 km·h− 1). At rest, NZBC extract had no effect on the cardiovascular, physiological and metabolic responses. During moderate-intensity exercise, only lower systemic vascular resistance (15%) was observed in 50% of the participants based on the smallest worthwhile change analysis (P = 0.08 for the cohort with moderate effect size, d = 0.62). There was a significant correlation between fat oxidation during rest and moderate-intensity walking in the placebo and NZBC extract condition. There was a trend (P = 0.08) for the linear relationship between the walking-induced placebo respiratory exchange ratio and change in fat oxidation by intake of NZBC extract. In Southeast Asian women, 14-day anthocyanin-rich NZBC extract did not elicit consistent cardiorespiratory and metabolic effects, although some participants showed reduced systemic vascular resistance. It is possible that there was not the bioavailability of plasma anthocyanin-induced metabolites that could alter cell function for metabolic responses. Further research should optimize dosing strategies and examine the roles of ethnicity, sex, and anthocyanin-induced metabolite bioavailability in shaping responsiveness to the intake of anthocyanins.

Introduction Anthocyanin-rich blackcurrant extract altered exercise-induced metabolic responses (e.g., enhanced fat oxidation) in case studies with Caucasian non-heat acclimatized male endurance athletes. We examined 2-3 weeks before marathon competition the effects of 7-day intake of the extract (i.e., 420 mg of anthocyanins per day) during supine rest and 1 h of moderate-intensity running in an elite national level female Southeast Asian endurance athlete (age: 48 years, BMI: 19.3 kg·m-2, body fat: 21.8%, V˙O2max : 44.4 mL·kg-1·min-1, 28 marathons since 2017) living and training outdoors in Thailand. Methods Non-invasive beat-to-beat hemodynamic monitoring (PhysioFlow®) and breath-by-breath gas technology (Cortex Metalyzer 3B) techniques were used during supine rest and a 1-hour indoor (∼24.5 °C, relative humidity: ∼42%) treadmill run at 50% V˙O2max (7.5 km·h-1) with blood lactate (XPER L1) taken 3 min on completion. Study was single-blind and placebo-controlled with final intake of the extract 2 h before starting the treadmill run. Results During rest, the blackcurrant extract condition was associated with higher heart rate (+6 bpm), cardiac output (+10%), carbohydrate oxidation (+31%), and respiratory exchange ratio (+0.02 units), with lower systemic vascular resistance (-18%) compared with placebo. Stroke volume, oxygen uptake, and fat oxidation values appeared similar between conditions. During the 1-h treadmill run at 50% V˙O2max , the blackcurrant extract condition was associated with higher stroke volume (+9%), cardiac output (+10%), oxygen uptake (+6%), carbohydrate oxidation (+43%), and respiratory exchange ratio (+0.03 units), with lower systemic vascular resistance (-24%) and fat oxidation (-7%) compared with placebo. Heart rate and rating of perceived exertion values appeared similar between conditions. Post-run lactate concentration was 59% lower in the blackcurrant extract condition (placebo: 1.7 ± 0.1 mMol·L-1; extract: 0.7 ± 0 mMol·L-1). Discussion This case study provided preliminary observations that a highly endurance-trained elite National Southeast Asian female athlete responded physiologically to the intake of blackcurrant extract. Seven-day intake with 420 mg per day of blackcurrant anthocyanins was associated with alterations in cardiovascular, metabolic, and respiratory responses during rest and moderate-intensity running, including lower post-run lactate concentrations. However, the mechanisms underlying this observation remain unclear and should be interpreted cautiously given the exploratory single-participant design.

Long COVID is characterized by persistent symptoms and physiological impairments beyond acute infection. Oxygen consumption (VO₂) and ventilatory efficiency, key indicators of cardiorespiratory fitness, are commonly diminished in this population, contributing to exercise intolerance. This study compared cardiorespiratory patterns and exercise capacity among individuals with Long COVID (LCG), those with resolved symptoms (Short COVID; SCG), and healthy controls (CG). The secondary objective was to assess longitudinal changes over six months. Cross-sectional comparisons at baseline addressed the primary objective, while the longitudinal component explored on changes over time. Participants included 94 in the LCG, 100 in the SCG, and 70 in the CG. All performed a 6-minute walk test (6MWT) during which peak oxygen uptake (VO₂peak), minute ventilation (VE), and VE/VCO₂ (ratio of VE to carbon dioxide output, reflecting ventilatory efficiency) were continuously measured using the Metamax 3B system. Baseline differences were assessed by one-way ANOVA, and longitudinal changes by generalized estimating equations. At baseline, VO₂peak was significantly reduced in the LCG (70.1 % predicted) versus SCG (80.6 %) and CG (84.6 %) (p = 0.001). VE/VCO₂ was elevated in the LCG (30.2 ± 4.2) compared to SCG (27.9 ± 2.8) and CG (28.7 ± 3.3) (p < .001). The 6MWT distance was also lower in the LCG (484 ± 127 m) than SCG (607 ± 69.1 m) and CG (571 ± 89.6 m) (p < .001). No statistically significant Group × Time interaction emerged between the groups. Individuals with Long COVID exhibited persistent ventilatory inefficiency and reduced exercise capacity, with impairments persisting over six months, underscoring the need for targeted rehabilitation. SHORT ABSTRACT: Individuals with Long COVID exhibit reduced exercise capacity and persistent ventilatory inefficiency compared to Short COVID and control groups. At baseline and over six months, VO₂, VE/VCO₂, and 6MWT distances were significantly impaired, highlighting the need for targeted rehabilitation strategies to address ongoing physiological limitations in this population.

The Paleolithic diet (PD) has positive effects on health status and body composition. The Paleo diet has been also used to assess the effects on handball players performance but the association of adherence to PD and resting metabolic rate (RMR) has not been investigated especially in this group. This study aimed to impact of the moderate-carbohydrate diet on RMR among professional handball players. Twenty-five handball players were assigned into two groups: 14 in the experimental group (the Paleo diet; PD) and 11 in the control group (rational diet; CD) for 8-weeks of normoenergetic nutritional intervention. Resting metabolic rate was measured by indirect calorimetry using a Cortex MetaLyzer 3R ergospirometer (Germany), using the breath-by-breath method. Oxygen uptake (VO2), carbon dioxide production (VCO2), respiratory quotient (RQ), RMR, and substrate utilization (carbohydrate, fat, protein) and energy expenditure from each substrate were measured during the measurement. There were no differences in RMR parameters, as well as VO2 (L/min), VCO2 (L/min), RQ, substrate utilization (g/day): CHO, PRO, FAT, and EE (kcal/hour) from each substrate between PD and CD groups. Eight weeks of a normoenergetic Paleo diet did not affect resting metabolic rate.

Background This study aims to calculate and compare aerobic and anaerobic energy expenditure in women participating in recreational mini-trampoline activities. Methods Thirteen women volunteered to participate in this study. Cardiorespiratory and metabolic variables—including V̇O2 (L/min), V̇O2/kg (ml/min/kg), V̇O2/HR (ml/beat), HR (bpm), V̇E/V̇O2, V̇E/V̇CO2, RER, V̇E (L/min), FAT (g/h), METs, and V̇CO2 (L/min) were measured using a portable gas analyzer (Cortex Metamax 3B). The mini-trampoline protocol was structured to progressively increase exercise intensity over a 5-minute period (2 and a half min aerobic rhytym; 2 and a half min anaerobic rhytym intensity), with load progression achieved through gradual increases in jump amplitude and movement frequency. The exercise protocol was performed to an instrumental music track characterized by a constant tempo of 128 bpm, a regular 4/4 meter, distinct metrical accents, and no lyrics. Although the tempo was kept constant, rhythmic variations were utilized to distinguish between the aerobic and anaerobic phases. Data were analyzed using a paired-samples t-test to compare the phases, with statistical significance set at p < .05. Result As a result of the research, there were significant differencies found between Phase 1 (aerobic) and Phase 2 (anaerobic) according to V̇O2 (L/min), V̇O2/kg (ml/min/kg), V̇O2/HR (ml/beat), HR (bpm), V̇E/V̇O2, V̇E/V̇CO2, RER, V̇E (L/min), FAT (g/h), METS, V̇CO2 (L/min) variables (p < .001). Conclusion Mini-trampoline exercise emerges as a robust and time-efficient training method capable of eliciting significant aerobic and anaerobic responses, alongside high energy expenditure. Trial registration Not applicable.

Background Although the existing field-based tests to assess functional capacity in dancesport have been developed, most of them have been applied to ballet or contemporary dancesport athletes at the individual level, while little evidence is available for dancesport couples in standard dance disciplines. Therefore, the main purpose of this study was to examine the test-retest reliability and usefulness of the progressive Ballroom Aerobic Test (BAT) protocol for assessing aerobic performance. Methods Thirteen standard dancesport athletes (six pairs and one individual male participant; age: 20.1 ± 3.8 years; height: 175.0 ± 8.2 cm; weight: 64.3 ± 9.7 kg; males; age: 19.9 ± 3.7 years; height: 180.0 ± 4.7 cm; weight: 70.2 ± 8.7 kg; body mass index: 21.5 ± 1.8 kg/m2 training experience: 8.6 ± 5.1 years; females; age: 20.3 ± 4.0 years; height: 168.5 ± 6.5 cm; weight: 57.5 ± 5.5 kg; body mass index: 20.2 ± 1.3 kg/m2; training experience: 8.5 ± 3.4 years) took part in the study. All participants were members of certified dancesport clubs who competed at national and international levels. The BAT protocol consisted of five stages, each corresponding to one of five standard dancesport disciplines (English Waltz, Slow Foxtrot, Tango, Viennese Waltz, and Quickstep). A test-retest design, with one week between trials, was used to examine the reliability measures. Ventilatory and metabolic parameters were derived from MetaMax® 3B, a reliable and valid portable gas analyzer. Reliability measures included Cohen D effect size (ES), intra-class correlation coefficient (ICC), coefficient of variation (CV), typical error (TE) and smallest worthwhile change (SWC). Results No significant differences were observed between test and retest sessions (P > 0.05). ESs ranged from trivial to small (0.00–0.47) with ‘very good’ to ‘excellent’ reliability (ICC = 0.80–0.99; CV = 1.63–4.85%). The usefulness of the BAT protocol was generally rated as ‘ok’ to ‘good’ for speed (TE = 2.76; SWC = 3.20; <), absolute VO2 (TE = 0.14; SWC = 0.15; <), respiratory exchange ratio (RER; TE = 0.02; SWC = 0.02; =), tidal volume (VT = 0.06; SWC = 0.06; =), and dead space to tidal volume ratio (VD/VT; TE = 0.01; SWC = 0.01; =). Conclusion Current findings suggest that the BAT protocol is a reliable and useful tool for assessing aerobic capacity in standard-style dancesport athletes. Moreover, the BAT protocol can accurately detect meaningful individual changes, particularly for speed (3.20 bpm), absolute VO2 (0.15 L*min−1), and VE (4.87 L). These results may assist athletes and strength and conditioning coaches in monitoring and tracking ‘real’ time changes to optimize the training process.

Introduction The study examined how exercise intensity and participants' characteristics influence the variability and test-retest reliability of pulmonary gas-exchange while providing domain-specific reliability benchmarks for exercise testing. Methods Forty-two healthy adults (V̇O2max = 49.6 ± 8.8 ml·kg-1·min-1) completed a ramp incremental exercise test and six 6-min constant work-rate cycling trials distributed across moderate, heavy, and severe exercise intensities. Exercise intensities were set at 33%Δ and 66%Δ between baseline and gas exchange threshold (GET), GET and respiratory compensation point (RCP), and RCP and V̇O2max, respectively. Pulmonary oxygen uptake (V̇O2), carbon dioxide output (V̇CO2), and ventilation (V̇E) were recorded using two metabolic carts. Systematic differences between days and intensities were assessed with two-way repeated-measures ANOVA. Variability and participants' characteristics were examined with within-trial coefficient of variation (CV%), Pearson correlations, linear mixed-effects models (LMME), intraclass correlation coefficient (ICC), standard error of measurement (SEM), minimal detectable change (MDC), and Bland-Altman analysis. Results V̇O2, V̇CO2, and V̇E increased with intensity (p ≤ 0.001), with no day-to-day differences (p > 0.05). CV% decreased progressively with intensity, from ∼7-10% in the moderate to <5% for V̇O2 and V̇CO2 in the severe domain. ICCs were excellent (>0.95) in the heavy and severe domains. Correlations showed moderate negative associations between CV% and aerobic fitness (r -0.34 and -0.58, p < 0.05), while LMME identified exercise intensity as the main factor associated with variability. MDC for V̇O2 ranged from 166 to 415 ml·min-1, and Bland-Altman plots confirmed minimal bias. Discussion exercise intensity influences the variability and reliability of breath-by-breath gas-exchange responses, with relative variability decreasing at higher metabolic loads. Fitness-related differences in CV% possibly reflect physiological scaling effects. These results provide practical reliability thresholds and improve the interpretation of repeated-measures testing in exercise physiology.

A growing number of portable devices has become available for daily physical activity and energy expenditure (EE) monitoring. Although several studies have examined EE estimation using heart rate (HR) and accelerometry (ACC), no study to date has explored EE prediction based on HR and ACC data measured simultaneously in the ear canal by a single commercial wearable device. Therefore, the aim of this study was to assess the feasibility of estimating EE using the cosinuss° in-ear sensors °One and °Two. Twenty-four healthy adults (12 female, 12 male, age 26.91 ± 2.91 years, body mass 65.43 ± 8.01 kg) completed two test sessions: a laboratory treadmill test (Modified Bruce Protocol) and an outdoor walking test consisting of three phases (uphill at comfortable pace, downhill at comfortable pace, and uphill as fast as possible). EE was measured by the portable indirect calorimetry device MetaMax 3B (criterion measure), while HR and ACC were recorded continuously by the in-ear sensors °One and °Two. Linear mixed-effects models were developed from laboratory data and applied to outdoor walking data from the same participants (participant-calibrated prediction). Prediction accuracy was assessed using root mean square error (RMSE), mean absolute percentage error (MAPE), and Bland-Altman analysis. Both in-ear sensors showed preliminary potential for EE prediction during outdoor walking. The integration of HR, ACC, and biological sex produced the best-fitting calibration models, with marginal R² values of 0.79 and 0.80 for °One and °Two respectively. In the outdoor walking test, no significant systematic bias was detected across conditions (p > 0.05). However, prediction accuracy was variable across conditions and subgroups, with MAPE ranging from 22% to 37% for °One and 22% to 38% for °Two (following exclusion of one participant with implausible reference data in the Down phase). Pearson correlation coefficients were stronger for female participants, while male subgroup correlations were weak or negative in several conditions, limiting conclusions about individual-level prediction accuracy for this subgroup. The cosinuss° in-ear sensors demonstrated preliminary feasibility for group-level EE estimation during outdoor walking, with accuracy broadly comparable to several commercial wrist-worn devices. Given the variable prediction accuracy, particularly for male participants and during downhill walking, further validation with larger and more diverse samples is needed before clinical or sports application.

Altitude training camps are a popular measure to enhance endurance performance at sea level. This study elucidates the effects of acute altitude-induced hypoxia, running speed and surface on cadence, peak tibial acceleration (PTA), gait asymmetry and residual shock in distance running. Ten healthy, trained native lowlanders (6 males, 4 females; 28.2 ± 9.2 years; mean V˙O2,peak of 54.9 ± 5.9 mL min−1 kg−1) participated in this study. They ran 1500 m bouts of at 50, 1000 and 2300 m above mean sea level on paved roads and natural trails at three different speeds. Those speeds were chosen to represent the most common training zones and were defined as v1=90%⋅vVT1, v2=12vVT1+vVT2 and v3=100%⋅vVT2, with vVT1 and vVT2 denoting the speeds at the ventilatory thresholds 1 and 2. Based on the experimental results, cadence increased by +2.2 spm per +1 km h−1 (p < 0.001) and fell by −1.1. spm per +1000 m of elevation (p < 0.001), whereas surface did not show any significant effect. Likewise, PTA was not affected by surface, but grew by 0.9 g per +1 km h−1 (p < 0.001), and decreased by −0.6 g per +1000 m in elevation, with significant effects particularly at speeds beyond vVT1 (p < 0.049). Absolute lateral asymmetry was not altered by elevation, surface or running speed. Mean shock attenuation increased with running speed by +2.5 percentage points per +1 km h−1 (p < 0.001) but was independent of elevation and surface. In essence, running speed seems to be the predominant factor defining biomechanical loading, even under acute hypoxia and for varying surface conditions.

Introduction Accurately measuring aerobic endurance in military and police Special Operations Forces (SOF) and in load-bearing sports requires a cardiopulmonary exercise test protocol that incorporates load and terrain demands. We developed a ramped treadmill test incorporating a 12.6 kg vest and incremental incline and evaluated its validity against a standard speed-ramped protocol. Materials and Methods Twenty-three healthy and trained volunteers completed both protocols in randomized order. Breath-by-breath V˙O2 and heart rate data at the ventilatory thresholds 1 and 2, as well as V˙O2max were compared using Bland-Altman plots, two one-sided tests (TOST), as well as Bayesian range of practical equivalence (ROPE) using ±2.84 ml/kg/min (V˙O2) and ±3.1% (HR) pre-defined boundaries for insignificant difference. Results Mean test duration was 710 ± 85 sec with both protocols. V˙O2max differed by –0.2 ml/kg/min (95% CI –1.3 to 0.9). TOST did not confirm strict equivalence, but Bayesian ROPE placed 100% of the posterior within ± 2.84 ml/kg/min. Submaximal V˙O2@VT2 and HR thresholds met 95% ROPE criteria; V˙O2@VT1 narrowly missed. Conclusions A vest-loaded, incline-ramped CPET designed for SOF tasks and sports disciplines that involve carrying additional load produces practically equivalent values of V˙O2max compared to a traditional speed-ramped protocol. The new protocol allows for accurate V˙O2 and heart rate measures for SOF and athletes carrying weight on steep terrain, while also providing a task-specific experience.

Purpose The aim of the present study was to identify blood-based biomarkers that could predict individual VO₂max improvement before the start of an artificial altitude training camp. Methods In an exploratory intervention study, 15 young highly trained athletes from the German Athletics Federation completed a 21-day Live High – Train Low program at an artificial altitude house, which simulated an altitude of 800 km·h (approximately 1.900–2.500 m) under normobaric hypoxia. VO₂max was measured pre- and post-intervention, and blood parameters were collected at six time points (pre, post and four times at altitude). The pre measurement functioned as baseline and was used for the predictive model. Results Altitude training led to a mean VO₂max increase of 2.1 mL · kg⁻¹ · min⁻¹ (+ 3.1%), with high interindividual variability (–1.7 to + 4.5 mL · kg⁻¹ · min⁻¹). Neither training load, sex, nor discipline explained these differences. Logistic regression analyses identified monocyte percentage (> 10%) and neutrophil percentage (> 50%) emerged as the strongest predictors of responder status (McFadden's R² = 0.61 and 0.65, respectively), while neutrophil-to-lymphocyte-ratio (NLR) and hematocrit also showed significant predictive value. Threshold analyses revealed that high-responders consistently displayed lower neutrophil activity (NLR < 1.5) and higher hematocrit levels (> 42.5%), in contrast to low-responders. Longitudinal biomarker trajectories further supported these distinctions, with high-responders maintaining adaptive immune and iron-related profiles, whereas low-responders exhibited persistent signs of innate immune activation and suboptimal erythropoietic status. Conclusion These results highlight the relevance of functional biomarker profiles for individualized training planning in elite sports. Practically, this opens new possibilities for the targeted use of altitude training while minimizing health risks. Keywords: Hypoxia · Athletes · Monocytes · NLR · Iron metabolism · Endurance performance

Objectives This study aimed to assess relationships of acute responses to short-format high-intensity interval training (HIIT) with the anaerobic speed reserve (ASR) of adolescent runners. Design Pre-post intervention design. Methods Eighteen highly-trained youth runners (15.83 ± 0.86 years) underwent maximal sprinting speed (MSS) and maximal aerobic speed (MAS) assessments to determine ASR (MSS minus MAS) and a standardized HIIT protocol (2 × (20 × 15 s/15 s @110 % MAS)) was administered. Pre/post-HIIT assessments included biochemical (i.e., creatine kinase (CK)), neuromuscular (countermovement jump, CMJ; reactive strength index, RSI), cardiac (i.e., heart rate recovery (HRR)), and athlete-reported outcome measures (e.g., single item for fatigue). Pearson's r was calculated to assess relationships between acute responses and ASR, MSS, MAS, and relative intensity of the HIIT (%ASR). Results Athletes' ASR and %ASR were significantly associated with the pre/post difference of CK (r = -0.75; p < 0.001; r = 0.74; p < 0.001, respectively), CMJ height, and RSI (r ≥ 0.69; p ≤ 0.002; r ≤ -0.49; p ≤ 0.04, respectively). However, HRR did not correlate significantly with ASR or %ASR (r ≤ 0.37, p ≥ 0.131, r ≥ -0.31; p ≥ 0.22, respectively). The pre/post difference of RSI correlated with MAS (r = -0.54; p = 0.02), and the pre/post difference of CK (r = -0.50; p = 0.034) and of CMJ height (r = 0.76; p < 0.001) with MSS. Regarding athlete-reported measures, ASR and %ASR showed significant associations with most fatigue and recovery variables (r ≥ 0.57; p ≤ 0.014, r ≥ 0.57; p ≤ 0.013, respectively). The pre/post difference of the single item for fatigue showed a positive relationship with MSS (r = 0.49; p = 0.037). Conclusions Acute biochemical, neuromuscular, and athlete-reported responses to short-format HIIT showed strong relationships with ASR and MSS, indicating higher internal load in athletes with a lower ASR and MSS by using a higher %ASR, compared to athletes with a higher ASR and MSS. These findings can help to tailor training programs to individual needs and avoid possible overload.

Rationale: In the outpatient setting, the six minute walk test (6MWT) is the most performed measure of exercise capacity in those with pulmonary hypertension (PH). The 6MWT is presumed to be submaximal compared to the peak-exercise response achieved with a cardiopulmonary exercise test (CPET), however this assumption has not been verified across a broad range of six-minute walk distances (6MWD) in a large sample of PH patients. The aim of this study was to compare the cardiopulmonary responses recorded during, and at the end, of a 6MWT and a CPET in individuals with PH. Methods: On separate days, 60 individuals (50 females) with stable PH (Age: 49±16yr; Functional Class I-III, mean pulmonary artery pressure: 45±18mmHg) completed a 6MWT and an incremental maximal CPET on a recumbent cycle (Lode). Cardiopulmonary measurements were made using open circuit spirometry (Cortex Metamax) and averaged over 30s. Both end exercise and within test measurements of oxygen consumption (V̇O2), carbon dioxide production (V̇CO2), ventilation (V̇E), breathing efficiency (V̇E/V̇CO2), heart rate (HR), O2 pulse, oxygen saturation (SpO2), and dyspnoea were compared between tests. Results: The 6MWD ranged from 350-758m and the CPET peak power between 40-120W. While the mean duration of the CPET (8.7 ± 0.7min) was significantly longer than the 6MWT, participants achieved a similar end-exercise V̇O2, V̇E/V̇CO2, HR, O2 Pulse and SpO2 (Table 1). Participants did achieve a significantly (p<0.05) higher V̇CO2, V̇E and dyspnoea at the completion of the CPET (Table 1). Notably, the end-exercise V̇O2 (L. min-1, mL. kg-1. min-1 and %predicted) achieved during each test were not significantly different (Table 1). However, at similar time points during each test, the 6MWT had a significantly higher V̇O2, V̇CO2, V̇E, HR and O2 pulse when compared to the CPET. During the final 90s of the 6MWT participants sustained a V̇O2 (15.9 ± 4.2 mL. Kg-1. min-1) and HR (133 ± 23 beats. min-1) response that was not significantly different (both p>0.15) to that achieved at the end of the CPET (Table 1). Conclusions: Our data suggest that PH patients achieve a similar peak V̇O2 and HR response during the 6MWT as they would on a recumbent cycle ergometer. Whilst the duration of the 6MWT may be shorter than the CPET, individuals with PH are required to sustain a near maximal response for a substantially longer period (over 90s) that may compromise their oxygen transport and utilisation capacity during exercise.

Purpose Portable metabolic systems are used as the “gold standard” for measuring energy expenditure (EE) in the development and validation of wearable devices. This study aimed to compare EE measurements obtained using the COSMED K5 (K5) and CORTEX METAMAX 3B (M3B) during the resting state and submaximal-intensity exercise in women without self-reported regular exercise training. Methods Twenty women aged 21.4 ± 1.5 years completed two measurements, including resting in a seated position and cycling on a simple upright ergometer at 30 W, 40 W, 50 W, and 60 W. Average EE and other metabolic parameters were compared between K5 and M3B. Differences between K5 and M3B were assessed using the paired-samples t-test, and the effect size was calculated as Cohen’s d. Agreement between the two systems was evaluated by calculating Pearson correlation coefficients and visually examining Bland–Altman plots. Results The number of participants who completed resting and exercise measurements was 18 and 19, respectively. For resting EE, the mean values measured using K5 were 33.4% higher than those measured using M3B (p < 0.001, Cohen’s d = 1.47). Similar differences were observed for cycling at 30 W (15.8%, p < 0.001, Cohen’s d = 1.50), 40 W (16.1%, p < 0.001, Cohen’s d = 1.68), 50 W (14.8%, p < 0.001, Cohen’s d = 1.28), and 60 W (14.6%, p < 0.001, Cohen’s d = 1.29). Pearson correlation coefficients between EE measured using K5 and M3B was 0.66 for 30 W cycling (p = 0.002) and 0.62 for 40 W cycling (p = 0.005). Conclusion K5 and M3B show significant differences in EE measurements during rest and exercise among untrained female individuals, indicating systematic bias in EE measurement between the two systems. Thus, careful consideration is essential when interpreting the results of wearable device studies that use different automated metabolic systems.

Walking is the most accessible and common type of physical activity. Exercising at one’s self-selected intensity could provide long-term benefits as compared to following prescribed intensities. The aim of this study was to simultaneously examine metabolic, perceptual, spatiotemporal and stability parameters at an absolute 3 km·h−1 speed range around the individual preferred walking speed (PWS). Thirty-four young sedentary adults (18 women) volunteered to walk at seven speeds relative to their PWS in 3-min trials interspaced with 3-min rest intervals. Results indicated a significant main effect of speed on all studied variables. While metabolic, perceptual and spatiotemporal values were sensitive to the smallest change in speed (i.e., 0.5 km·h−1), a significant increase in the rate of carbohydrate oxidation and decrease in %fat oxidation were only observed at speeds above PWS. Results also revealed significantly higher coefficients of variation for stride characteristics at speeds below PWS only. Moreover, analyses of best fit models showed a quadratic relationship between most variables and speed, with the exceptions of metabolic cost of transport, rating of perceived exertion and stride duration that changed exponentially with speed. PWS coincided with optimized mechanical efficiency, fuel oxidation and gait stability. This indicated that walking below PWS decreased both mechanical efficiency and stability of gait, while walking above PWS increased carbohydrate oxidation. Those factors seem to play an important role as determinants of PWS. We suggest that walking at PWS may provide benefits in terms of fat oxidation while optimizing gait stability.

This study aims to assess the reliability and accuracy of a novel portable cardiopulmonary function meter, “Booster,” developed by our research group, across various exercise intensities and modalities. The study was segmented into reliability and validity assessments. Twenty-two male participants underwent reliability testing, conducting two sequential tests on a treadmill while wearing the Booster to measure VO2 and VE among other parameters at increasing intensities. For validity testing, 64 participants were randomly divided into treadmill and cycle ergometer groups, with tests conducted using both the Booster and the Cortex Metalyzer 3B systems. Overall, the Booster demonstrated high retest reliability for VO2 and VE measurements during treadmill exercises, albeit showing poor consistency during rest and low-intensity exercise phases. Validity testing indicated no significant differences in VO2 and VE measurements between Booster and Cortex Metalyzer 3B across all exercise stages on both treadmill and cycle ergometer, suggesting good correlation. However, discrepancies in measurements between Booster and Cortex Metalyzer 3B were observed during rest and maximal exertion phases. The Booster exhibits commendable reliability and stability during most treadmill exercise phases and shows generally acceptable validity compared to the Cortex Metalyzer 3B system. Nonetheless, potential measurement discrepancies may occur during rest and maximal exertion conditions.

This study aimed to evaluate the effect of repeated sprint in hypoxia (RSH) training in mask vs. tent system on the physiological parameters associated with the cyclist’s performance. Sixteen well-trained cyclists (VO2max 66 ± 5.9 mL/kg/min) participated in a randomised and two parallel groups design. Participants were assigned to different hypoxia methods [RSHMask (n = 8) vs RSHTent (n = 8)]. The sprint number and power output were measured during a repeated sprint test to failure before and after the effect of eight sessions of RSH. In addition, the following physiological parameters were evaluated: oxygen consumption (VO2), heart rate (HR), arterial oxygen saturation (SpO2), muscle oxygen saturation (SmO2), lactate and core temperature (CoreT°). Linear mixed models were used for repeated measures (p value < 0.05), and the effect size (ES) between groups was reported. An inter-individual analysis of participants was also reported. There was an increase in sprint numbers in both groups (ES = 0.167, p = 0.023) and an increase in power output (∑w) in the RSHMask group (ES = 0.095, p = 0.038). The RSHMask group showed improvement in VO2 recovery (ES = 0.096, p = 0.031) and SmO2 desaturation % (ES = 0.112, p = 0.042) compared to the RSHTent group. Likewise, 50% of the participants in RSHTent showed adaptations to withstand higher T°Core (+ 0.45°), and eight participants showed lactate decreases between 2.9 and 3.1 mmol/L (−24%) after RSH in both groups. Generally, RSH improves the cyclist’s performance, whether the mask or tent method is used. However, RSHTent has the advantage of causing adaptations in T°Core, whilst RSHMask improves anaerobic performance in the oxygenation of peripheral muscles.

Aims Left atrial (LA) and ventricular (LV) remodelling is thought to be balanced in healthy individuals, and the LA end-systolic volume (LAV) to LV end-diastolic volume (LVEDV) ratio (LA:LV) could help discriminate between pathological and physiological LA enlargement. We aimed to assess LA:LV and its associations with age, sex, and cardiovascular risk factors HbA1C, body mass index (BMI), systolic blood pressure, and peak oxygen uptake (VO2peak). The association to measures of LV diastolic function and filling pressures were compared with LAV and LA reservoir strain. Methods and results Cardiopulmonary exercise testing and measurement of risk factors 10 years apart and echocardiography at follow-up was performed in 1348 healthy adults [52% women, mean (SD) age 59 (12) years] prospectively included in a large population study. All risk factors were significantly associated with LA:LV in univariate analyses, while BMI and VO2peak were significantly associated with LA:LV in adjusted models. A higher LA:LV was associated with increased odds ratio (OR) of diastolic dysfunction [OR (95% CI) 2.6 (2.1, 3.3)]. Measures of LV filling pressures were more closely associated with LA:LV than LAV and LA reservoir strain, but LA reservoir strain was more closely related to some diastolic function measures. In individuals with LAV > 34 mL/m2, the LA:LV explained 29% of variance in VO2peak (P < 0.001). Conclusion A higher LA:LV was associated with, and may improve, assessment of diastolic dysfunction and filling pressures. The LA:LV differentiates VO2peak in individuals with enlarged LAV and may have a role in evaluating whether LA enlargement reflects pathology.

The acute myocardial infarction (AMI) present high mortality rate that may be reduced with cardiac rehabilitation. Despite its good establishment in outpatient care, few studies analyzed cardiac rehabilitation during hospitalization. Thus, this study aims to clarify the safety and efficacy of early cardiac rehabilitation after AMI. This will be a clinical, controlled, randomized trial with blind outcome evaluation and a superiority hypothesis. Twenty-four patients with AMI will be divided into two groups (1:1 allocation ratio). The intervention group will receive an individualized exercise-based cardiac rehabilitation protocol during hospitalization and a semi-supervised protocol after hospital discharge; the control group will receive conventional care. The primary outcomes will be the cardiac remodeling assessed by cardiac magnetic resonance imaging, functional capacity assessed by maximal oxygen consumption, and cardiac autonomic balance examined via heart rate variability. Secondary outcomes will include safety and the total exercise dose provided during the protocol. Statistical analysis will consider the intent-to-treat analysis. Trial registration. Trial registration number: Brazilian Registry of Clinical Trials (ReBEC) (RBR- 9nyx8hb).

Purpose Peak oxygen uptake (VO2peak) is a crucial health marker, extensively studied in adults for its prognostic value. However, its significance in the older persons, especially octogenarians, remains underexplored due to limited representation in research. This study aims to assess the predictive power of VO2peak for survival in individuals aged 80 and above. Methods We included individuals aged 80 or older who underwent cardiopulmonary exercise tests at a single center. Mortality rates were compared based on VO2peak relative to 80% of predicted values (%VO2peak). We employed three multivariate Cox regression models: Model 1 (unadjusted), Model 2 (adjusted for age) and Model 3 (adjusted for age and stroke). Results Among 188 participants (mean age 83.3 ± 3 years, 68.9% male), 22 (11.7%) passed away during a median follow-up of 494 days. Non-survivors tended to be older with lower VO2peak and %VO2peak. All models demonstrated associations between %VO2peak ≤ 80% and mortality: HR = 3.19 (95% CI: 1.30-7.86, p = 0.011) for M1; HR = 3.12 (95% CI: 1.26-7.74, p = 0.013) for M2 and HR = 2.80 (95% CI: 1.11-7.06, p = 0.028) for M3. Conclusion In the context of an aging population, this study underscores the enduring significance of VO2peak as a survival predictor among the older person, including octogenarians. These findings carry profound implications for tailoring healthcare strategies to address the evolving demographic landscape.

Purpose Cardiopulmonary exercise testing (CPET) is considered the gold standard for assessing cardiorespiratory fitness. To ensure consistent performance of each test, it is necessary to adapt the power increase of the test protocol to the physical characteristics of each individual. This study aimed to use machine learning models to determine individualized ramp protocols based on non-exercise features. We hypothesized that machine learning models will predict peak oxygen uptake (V̇ V ˙ O2peak) and peak power output (PPO) more accurately than conventional multiple linear regression (MLR). Methods The cross-sectional study was conducted with 274 (♀168, ♂106) participants who performed CPET on a cycle ergometer. Machine learning models and multiple linear regression were used to predict V̇ V ˙ O2peak and PPO using non-exercise features. The accuracy of the models was compared using criteria such as root mean square error (RMSE). Shapley additive explanation (SHAP) was applied to determine the feature importance. Results The most accurate machine learning model was the random forest (RMSE: 6.52 ml/kg/min [95% CI 5.21–8.17]) for V̇ V ˙ O2peak prediction and the gradient boosting regression (RMSE: 43watts [95% CI 35–52]) for PPO prediction. Compared to the MLR, the machine learning models reduced the RMSE by up to 28% and 22% for prediction of V̇ V ˙ O2peak and PPO, respectively. Furthermore, SHAP ranked body composition data such as skeletal muscle mass and extracellular water as the most impactful features. Conclusion Machine learning models predict V̇ V ˙ O2peak and PPO more accurately than MLR and can be used to individualize CPET protocols. Features that provide information about the participant's body composition contribute most to the improvement of these predictions. Trial registration number DRKS00031401 (6 March 2023, retrospectively registered).

This is the first study to assess longitudinal changes in anthropometric, physiological, and physical qualities of international women’s rugby league players. Thirteen forwards and 11 backs were tested three times over a 10-month period. Assessments included: standing height and body mass, body composition measured by dual x-ray absorptiometry (DXA), a blood panel, resting metabolic rate (RMR) assessed by indirect calorimetry, aerobic capacity (i.e., V ˙ O 2 max ) evaluated by an incremental treadmill test, and isometric force production measured by a force plate. During the pre-season phase, lean mass increased significantly by ~2% for backs (testing point 1: 47 kg; testing point 2: 48 kg) and forwards (testing point 1: 50 kg; testing point 2: 51 kg) (p = ≤ 0.05). Backs significantly increased their V ˙ O 2 max by 22% from testing point 1 (40 ml kg -1 min -1 ) to testing point 3 (49 ml kg -1 min -1 ) (p = ≤ 0.04). The V ˙ O 2 max of forwards increased by 10% from testing point 1 (41 ml kg -1 min -1 ) to testing point 3 (45 ml kg -1 min -1 ), however this change was not significant (p = ≥ 0.05). Body mass (values represent the range of means across the three testing points) (backs: 68 kg; forwards: 77–78 kg), fat mass percentage (backs: 25–26%; forwards: 30–31%), resting metabolic rate (backs: 7 MJ day -1 ; forwards: 7 MJ day -1 ), isometric mid-thigh pull (backs: 2106–2180 N; forwards: 2155–2241 N), isometric bench press (backs: 799–822 N; forwards: 999–1024 N), isometric prone row (backs: 625–628 N; forwards: 667–678 N) and bloods (backs: ferritin 21–29 ug/L, haemoglobin 137–140 g/L, iron 17–21 umol/L, transferrin 3 g/L, transferring saturation 23–28%; forwards: ferritin 31–33 ug/L, haemoglobin 141–145 g/L, iron 20–23 umol/L, transferrin 3 g/L, transferrin saturation 26–31%) did not change (p = ≥ 0.05). This study provides novel longitudinal data which can be used to better prepare women rugby league players for the unique demands of their sport, underpinning female athlete health.

To establish the criterion‐assessed energy and fluid requirements of female netball players, 13 adult players from a senior Netball Super League squad were assessed over 14 days in a cross‐sectional design, representing a two‐ and one‐match microcycle, respectively. Total energy expenditure (TEE) and water turnover (WT) were measured by doubly labeled water. Resting and activity energy expenditure were measured by indirect calorimetry and Actiheart, respectively. Mean 14‐day TEE was 13.46 ± 1.20 MJ day−1 (95% CI, 12.63–14.39 MJ day−1). Resting energy expenditure was 6.53 ± 0.60 MJ day−1 (95% CI, 6.17–6.89 MJ day−1). Physical activity level was 2.07 ± 0.19 arbitrary units (AU) (95% CI, 1.95–2.18 AU). Mean WT was 4.1 ± 0.9 L day−1 (95% CI, 3.6–4.7 L day−1). Match days led to significantly greater TEE than training (+2.85 ± 0.70 MJ day−1; 95% CI, +1.00– +4.70 MJ day−1; p = 0.002) and rest (+4.85 ± 0.70 MJ day−1; 95% CI, +3.13–+6.56 MJ day−1; p < 0.001) days. Matches led to significantly greater energy expenditure (+1.85 ± 1.27 MJ; 95% CI, +0.95–+2.76 MJ day−1; p = 0.001) than court‐based training sessions. There was no significant difference in TEE (+0.03 ± 0.35 MJ day−1; 95% CI, −0.74–+0.80 MJ day−1; p = 0.936) across weeks. Calibrated Actiheart 5 monitors underestimated TEE (−1.92 ± 1.21 MJ day−1). Energy and fluid turnover were greatest on match days, followed by training and rest days, with no difference across weeks. This study provides criterion‐assessed energy and fluid requirements to inform dietary guidance for female netball players.

Context One acute bout of exercise leads to a rapid increase in the systemic cytokine concentration. Regular exercise might alter the cytokine response, in particular in beforehand untrained and obese individuals. Objective Using a proximity extension assay, we studied the effects of acute exercise as well as endurance training on a panel of 92 cytokines related to inflammation. Methods A total of 22 individuals (30 ± 9 years; peak oxygen uptake [VO2peak] 25.2 ± 4.2 mL/[kg × min]; body mass index [BMI] 31.7 ± 4.4) participated in an 8-week endurance exercise intervention. Blood samples were collected before and immediately after 30 minutes’ ergometer exercise at 80% VO2peak. Results Before and after the training intervention, 40 and 37 cytokines, respectively, were acutely increased more than 1.2-fold (Benjamini-Hochberg [BH]-adjusted P < .05). The exercise intervention did not change the acute increase in cytokines nor the resting cytokine levels, whereas fitness was improved and adiposity reduced. The increase in fitness led to a slight increase in power output when exercising at the same heart rate, which might explain the comparable increase in cytokines before and after the intervention. The largest acute increase was found for OSM, TGFA, CXCL1 and 5, and TNFSF14 (≥ 1.9-fold, BH-adjusted P < .001). The transcript levels of these proteins in whole blood were also elevated, particularly in the trained state. Only the acute increase in IL6 (1.3-fold) was related to the increase in lactate, confirming the lactate-driven secretion of IL6. Conclusion Our comprehensive proteomics approach detected several underexplored serum exerkines with up to now less understood function in the adaptation to exercise.

The aim of the study was to identify genetic variants associated with personal best scores in Turkish track and field athletes and to compare allelic frequencies between sprint/power and endurance athletes and controls using a whole-exome sequencing (WES) approach, followed by replication studies in independent cohorts. The discovery phase involved 60 elite Turkish athletes (31 sprint/power and 29 endurance) and 20 ethnically matched controls. The replication phase involved 1132 individuals (115 elite Russian sprinters, 373 elite Russian endurance athletes (of which 75 athletes were with VO2max measurements), 209 controls, 148 Russian and 287 Finnish individuals with muscle fiber composition and cross-sectional area (CSA) data). None of the single nucleotide polymorphisms (SNPs) reached an exome-wide significance level (p < 2.3 × 10−7) in genotype–phenotype and case–control studies of Turkish athletes. However, of the 53 nominally (p < 0.05) associated SNPs, four functional variants were replicated. The SIRT1 rs41299232 G allele was significantly over-represented in Turkish (p = 0.047) and Russian (p = 0.018) endurance athletes compared to sprint/power athletes and was associated with increased VO2max (p = 0.037) and a greater proportion of slow-twitch muscle fibers (p = 0.035). The NUP210 rs2280084 A allele was significantly over-represented in Turkish (p = 0.044) and Russian (p = 0.012) endurance athletes compared to sprint/power athletes. The TRPM2 rs1785440 G allele was significantly over-represented in Turkish endurance athletes compared to sprint/power athletes (p = 0.034) and was associated with increased VO2max (p = 0.008). The AGRN rs4074992 C allele was significantly over-represented in Turkish sprint/power athletes compared to endurance athletes (p = 0.037) and was associated with a greater CSA of fast-twitch muscle fibers (p = 0.024). In conclusion, we present the first WES study of athletes showing that this approach can be used to identify novel genetic markers associated with exercise- and sport-related phenotypes.

Background Post-COVID-19 exercise intolerance is poorly understood. Cardiopulmonary exercise testing (CPET) can identify the underlying exercise limitations. Objectives To evaluate the source and magnitude of exercise intolerance in post-COVID-19 subjects. Methods Cohort study assessing subjects with different COVID-19 illness severities and a control group selected by propensity score matching. In a selected sample with CPET prior to viral infection, before and after comparisons were performed. Level of significance was 5% in the entire analysis. Results One hundred forty-four subjects with COVID-19 were assessed (median age: 43.0 years, 57% male), with different illness severities (60% mild, 21% moderate, 19% severe). CPET was performed 11.5 (7.0, 21.2) weeks after disease onset, with exercise limitations being attributed to the peripheral muscle (92%), and the pulmonary (6%), and cardiovascular (2%) systems. Lower median percent-predicted peak oxygen uptake was observed in the severe subgroup (72.2%) as compared to the controls (91.6%). Oxygen uptake differed among illness severities and controls at peak and ventilatory thresholds. Conversely, ventilatory equivalents, oxygen uptake efficiency slope, and peak oxygen pulse were similar. Subgroup analysis of 42 subjects with prior CPET revealed significant reduction in only peak treadmill speed in the mild subgroup and in oxygen uptake at peak and ventilatory thresholds in the moderate/severe subgroup. By contrast, ventilatory equivalents, oxygen uptake efficiency slope, and peak oxygen pulse did not change significantly. Conclusions Peripheral muscle fatigue was the most common exercise limitation etiology in post-COVID-19 patients regardless of the illness severity. Data suggest that treatment should emphasize comprehensive rehabilitation programs, including aerobic and muscle strengthening components.

Pathogens such as severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2), influenza, and rhinoviruses are transmitted by airborne aerosol respiratory particles that are exhaled by infectious subjects. We have previously reported that the emission of aerosol particles increases on average 132-fold from rest to maximal endurance exercise. The aims of this study are to first measure aerosol particle emission during an isokinetic resistance exercise at 80% of the maximal voluntary contraction until exhaustion, second to compare aerosol particle emission during a typical spinning class session versus a three-set resistance training session. Finally, we then used this data to calculate the risk of infection during endurance and resistance exercise sessions with different mitigation strategies. During a set of isokinetic resistance exercise, aerosol particle emission increased 10-fold from 5,400 ± 1,200 particles/min at rest to 59,000 ± 69,900 particles/min during a set of resistance exercise. We found that aerosol particle emission per minute is on average 4.9-times lower during a resistance training session than during a spinning class. Using this data, we determined that the simulated infection risk increase during an endurance exercise session was sixfold higher than during a resistance exercise session when assuming one infected participant in the class. Collectively, this data helps to select mitigation measures for indoor resistance and endurance exercise classes at times where the risk of aerosol-transmitted infectious disease with severe outcomes is high.

Purpose: The purpose of this study is to provide comprehensive reference values for oxygen uptake efficiency slope (OUES) in healthy adults. International heterogeneity was also explored through published databases. Methods: A cross-sectional study was conducted with treadmill cardiopulmonary exercise testing (CPX) from a Brazilian healthy adult sample, in which absolute OUES and values normalized by weight and body surface area (BSA) were calculated. Data were stratified by sex and age group. Prediction equations were calculated using age and anthropometric variables. International data were pooled and differences were explored using factorial analysis of variance or the t test, as appropriate. The OUES age-related patterns were calculated using regression analysis. Results: A total of 3544 CPX were included (1970 males and 1574 females) and the age ranged from 20-80 yr. Males had higher values than females for OUES, OUES/kg, and OUES/BSA. Lower values were found with aging and the data followed a quadratic regression curve. Reference value tables and predictive equations were provided for absolute and normalized OUES in both sexes. International comparisons of absolute OUES values among Brazilian, European, and Japanese data revealed substantial heterogeneity. The OUES/BSA measure minimized the discrepancies between Brazilian and European data. Conclusions: Our study provided comprehensive OUES reference values in a large healthy adult sample from South America with a wide age range and included absolute and normalized values. Differences observed between Brazilian and European data were reduced in the BSA-normalized OUES.

Walking or balancing on a slackline has gained increasing popularity as a recreational and school sport, and has been found to be suitable for developing neuromuscular control. The metabolic requirements for neuromuscular control on slackline, however, have not been well described. Therefore, the aim of the study was to determine the metabolic demands of slacklining in less and more advanced slackliners. Nineteen slackliners performed several 4 min balance tasks: parallel and one‐leg stance on stable platform (2LS and 1LS), 1 leg stance on a slackline (1LSS), walking at a self‐selected speed and at a given speed of 15 m min−1 on a slackline (WSS and WGS). Expired gas samples were collected for all participants and activities using a portable metabolic system. During1 LS and 1LSS, there were 140% and 341% increases in oxygen uptake (V̇O2) with respect to V̇O2 rest, respectively. During slackline walking, V̇O2 increased by 460% and 444% at self‐selected and given speed, respectively. More advanced slackliners required mean metabolic demands 0.377 ± 0.065 and 0.289 ± 0.050 kJ·kg−1·min−1 (5.7 ± 0.95 and 3.9 ± 0.6 MET) for WGS and 1LSS, respectively, whilst less advanced slackliners, 0.471 ± 0.081 and 0.367 ± 0.086 kJ·kg−1·min−1 (6.4 ± 1.2 and 5.0 ± 1.1 MET) for WGS and 1LSS, respectively. Our data suggest that balancing tasks on slackline require V̇O2 corresponding to exercise intensities from light to moderate intensity. More advanced slackliners had a ∼25% reduced energy expenditure when compared with lower ability counterparts during simple balance tasks on the slackline.

Airborne respiratory aerosol particle transmission of pathogens such as severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2), influenza, or rhinoviruses plays a major role in the spread of infectious diseases. The infection risk is increased during indoor exercise, as aerosol particle emission can increase by more than 100-fold from rest to maximal exercise. Earlier studies have investigated the effect of factors such as age, sex, and body mass index (BMI), but only at rest and without taking ventilation into account. Here, we report that during both rest and exercise, subjects aged 60 to 76 y emit on average more than twice as many aerosol particles per minute than subjects aged 20 to 39 y. In terms of volume, older subjects emit on average five times as much dry volume (i.e., the residue of dried aerosol particles) than younger subjects. There was no statistically significant effect of sex or BMI within the test group. Together, this suggests that aging of the lung and respiratory tract is associated with an increased generation of aerosol particles irrespective of ventilation. Our findings demonstrate that age and exercise increase aerosol particle emission. In contrast, sex or BMI only have minor effects.

We report the complete time-course of cardiorespiratory fitness recovery back to baseline levels following 2 wk of head-down bed rest in 55- to 65-yr-old adults and found that multimodal training, consisting of high-intensity interval, aerobic and resistive exercises, performed throughout the 2 wk of head-down bed rest prevented reductions in cardiorespiratory fitness.

Pulmonary stenosis (PS) affects cardiopulmonary function and exercise performance. Cardiopulmonary exercise testing (CPET) together with transthoracic echocardiography (TTE) can measure exercise performance, PS progression, and treatment effects. We assessed exercise capacity in PS patients using these methods. We enrolled 28 PS patients aged 6–35 years who received surgery, balloon pulmonary valvuloplasty, and follow-up care. The control population was selected by a 1:1 matching on age, sex, and body mass index. Baseline and follow-up peak pulmonary artery pulse wave velocity (PAV) were compared using TTE. Initial CPET revealed no significant differences in anaerobic metabolic equivalent (MET), peak oxygen consumption (VO2), and heart rate recovery between the two groups, nor were significant differences in pulmonary function identified. Within the PS group, there were no significant differences in MET, peak VO2, and heart rate recovery between the baseline and final CPET. Similarly, no significant differences were observed between the baseline and final PAV. The exercise capacity of patients with properly managed PS was comparable to that of healthy individuals. However, during the follow-up, declining trends in pulmonary function, aerobic metabolism, and peak exercise load capacity were observed among adolescents with PS. This study provides long-term data suggesting that PS patients should be encouraged to perform physical activity. Regular reevaluation should also be encouraged to limit performance deterioration.

Background Persistent symptoms and exercise intolerance have been reported after COVID-19, even months after the acute disease. Although, the long-term impact on exercise capacity and health-related quality of life (HRQoL) is still unclear. Research question To assess the long-term functional capacity and HRQoL in patients hospitalized due to COVID-19. Study design and methods This is a prospective cohort study, conducted at two centers in Brazil, that included post-discharge COVID-19 patients and paired controls. The cohort was paired by age, sex, body mass index and comorbidities, using propensity score matching in a 1:3 ratio. Patients were eligible if signs or symptoms suggestive of COVID-19 and pulmonary involvement on chest computed tomography. All patients underwent cardiopulmonary exercise testing (CPET) and a HRQoL questionnaire (SF-36) 6 months after the COVID-19. The main outcome was the percentage of predicted peak oxygen consumption (ppVO2). Secondary outcomes included other CPET measures and HRQoL. Results The study sample comprised 47 post-discharge COVID-19 patients and 141 healthy controls. The mean age of COVID-19 patients was 54 ± 14 years, with 19 (40%) females, and a mean body mass index of 31 kg/m2 (SD, 6). The median follow-up was 7 months (IQR, 6.5–8.0) after hospital discharge. PpVO2 in COVID-19 patients was lower than in controls (83% vs. 95%, p = 0.002) with an effect size of 0.38 ([95%CI], 0.04–0.70). Mean peak VO2 (22 vs. 25 mL/kg/min, p = 0.04) and OUES (2,122 vs. 2,380, p = 0.027) were also reduced in the COVID-19 patients in comparison to controls. Dysfunctional breathing (DB) was present in 51%. HRQoL was significantly reduced in post COVID patients and positively correlated to peak exercise capacity. Interpretation Hospitalized COVID-19 patients presented, 7 months after discharge, with a reduction in functional capacity and HRQoL when compared to historical controls. HRQoL were reduced and correlated with the reduced peak VO2 in our population.

Objectives To compare the elicited exercise responses at ventilatory thresholds (VTs: VT1 and VT2) identified by cardiopulmonary exercise testing (CPET) in patients with cardiovascular disease (CVD) with the guideline-directed exercise intensity domains; to propose equations to predict heart rate (HR) at VTs; and to compare the accuracy of prescription methods. Methods A cross-sectional study was performed with 972 maximal treadmill CPET on patients with CVD. First, VTs were identified and compared with guideline-directed exercise intensity domains. Second, multivariate linear regression analyses were performed to generate prediction equations for HR at VTs. Finally, the accuracy of prescription methods was assessed by the mean absolute percentage error (MAPE). Results Significant dispersions of individual responses were found for VTs, with the same relative intensity of exercise corresponding to different guideline-directed exercise intensity domains. A mathematical error inherent to methods based on percentages of peak effort was identified, which may help to explain the dispersions. Tailored multivariable equations yielded r2 of 0.726 for VT1 and 0.901 for VT2. MAPE for the novel VT1 equation was 6.0%, lower than that for guideline-based prescription methods (9.5 to 23.8%). MAPE for the novel VT2 equation was 4.3%, lower than guideline-based methods (5.8%–19.3%). Conclusion The guideline-based exercise intensity domains for cardiovascular rehabilitation revealed inconsistencies and heterogeneity, which limits the currently used methods. New multivariable equations for patients with CVD were developed and demonstrated better accuracy, indicating that this methodology may be a valid alternative when CPET is unavailable.

Purpose Various systems are available for cardiopulmonary exercise testing (CPET), but their accuracy remains largely unexplored. We evaluate the accuracy of 15 popular CPET systems to assess respiratory variables, substrate use, and energy expenditure during simulated exercise. Cross‐comparisons were also performed during human cycling experiments (i.e., verification of simulation findings), and between‐session reliability was assessed for a subset of systems. Methods A metabolic simulator was used to simulate breath‐by‐breath gas exchange, and the values measured by each system (minute ventilation [V̇E], breathing frequency [BF], oxygen uptake [V̇O2], carbon dioxide production [V̇CO2], respiratory exchange ratio [RER], energy from carbs and fats, and total energy expenditure) were compared to the simulated values to assess the accuracy. The following manufacturers (system) were assessed: COSMED (Quark CPET, K5), Cortex (MetaLyzer 3B, MetaMax 3B), Vyaire (Vyntus CPX, Oxycon Pro), Maastricht Instruments (Omnical), MGC Diagnostics (Ergocard Clinical, Ergocard Pro, Ultima), Ganshorn/Schiller (PowerCube Ergo), Geratherm (Ergostik), VO2master (VO2masterPro), PNOĒ (PNOĒ), and Calibre Biometrics (Calibre). Results Absolute percentage errors during the simulations ranged from 1.15%–44.3% for V̇E, 1.05–3.79% for BF, 1.10%–13.3% for V̇O2, 1.07%–18.3% for V̇CO2, 0.62%–14.8% for RER, 5.52%–99.0% for Kcal from carbs, 5.13%–133% for Kcal from fats, and 0.59%–12.1% for total energy expenditure. Between‐session variation ranged from 0.86%–21.0% for V̇O2 and 1.14%–20.2% for V̇CO2, respectively. Conclusion The error of respiratory gas variables, substrate, and energy use differed substantially between systems, with only a few systems demonstrating a consistent acceptable error. We extensively discuss the implications of our findings for clinicians, researchers and other CPET users.

Maximal oxygen consumption (V̇O2max), physiological thresholds, and hemoglobin mass are strong predictors of endurance performance. High values of V̇O2max, maximal aerobic power (MAP), and power output at anaerobic thresholds are key variables in elite rowers. Endurance athletes often use altitude training as a strategy to improve performance. However, no clear evidence exists that training at natural altitude enhances sea-level performance in elite rowers. This study aimed to evaluate the effect of altitude training on rowing-performance parameters at sea level. The study was conducted on eleven rowers (Six females, five males) from the Chilean National Team during a 3-week moderate altitude training (∼2,900 m. a.s.l.) under the live high-train high (LHTH) model. It included a rowing ergometer maximal incremental test and blood analysis (pre and post-altitude). Gas exchange analysis was performed to measure V̇O2max, ventilatory thresholds (VTs) and rowing economy/efficiency (ECR/GE%). LHTL training improves performance-related variables at sea level (V̇Emax: 3.3% (95% CI, 1.2–5.5); hemoglobin concentration ([Hb]): 4.3% (95% CI, 1.7–6.9); hematocrit (%): 4.5% (95% CI, 0.9–8.2); RBC (red blood cells) count: 5.3% (95% CI, 2.3–8.2); power at VT2: 6.9% (95% CI, 1.7–12.1), V̇EVT2: 6.4% (95% CI, 0.4–12.4); power at VT1: 7.3% (95% CI, 1.3–13.3), V̇EVT1: 8.7% (95% CI, 1.6–15.8)) and economy/efficiency-related variables (ECRVT2: 5.3% (95% CI, −0.6 to −10.0); GE(%): 5.8% (95% CI, 0.8–10.7)). The LHTH training decreased breathing economy at MAP (−2.8% (95% CI, 0.1–5.6)), pVT2 (−9.3% (95% CI, −5.9 to −12.7)), and pVT1 (−9.3% (95% CI, −4.1 to −14.4)). Non-significant changes were found for V̇O2max and MAP. This study describes the effects of a 3-week moderate altitude (LHTH training) on performance and economy/efficiency-related variables in elite rowers, suggesting that it is an excellent option to induce positive adaptations related to endurance performance.

This study characterizes high-altitude training camps and their effect on the aerobic capacity of a Polish national team member (M.W.), who was a participant in the PyeongChang 2018 Winter Olympic Games (body weight: 59.6 kg, body height: 161.0 cm, fat mass: 10.9 kg and 18.3% of fat tissue, fat-free mass: 48.7 kg, muscle mass: 46.3 kg, and BMI = 23.0 kg/m2). The tests were conducted in the periods from April 2018 to September 2018 and April 2019 to September 2019 (period of general and special preparation). The study evaluated aerobic and anaerobic capacity determined by laboratory tests, a cardiopulmonary graded exercise test to exhaustion performed on a cycle ergometer (CPET), and the Wingate anaerobic test. Based on the research, training in hypobaric conditions translated into significant improvements in the skater’s exercise capacity recorded after participating in the Olympic Winter Games in Korea (February 2018). In the analyzed period (2018–2019), there was a significant increase in key parameters of aerobic fitness such as anaerobic threshold power output (AT-PO) [W]—223; power output POmax [W]—299 and AT-PO [W/kg]—3.50; (POmax) [W/kg]—4.69; and AT-VO2 [mL/kg/min]—51.3; VO2max [mL/kg/min]—61.0. The athlete showed high-exercise-induced adaptations and improvements in the aerobic metabolic potential after two seasons, in which four training camps were held in altitude conditions.

(1) Background: While previous studies revealed how underground mining might adversely affect the cardiopulmonary functions of workers, this study further investigated the differences between under- and aboveground mining at both high and low altitudes, which has received little attention in the literature. (2) Methods: Seventy-one healthy male coal mine workers were recruited, who had worked at least 5 years at the mining sites located above the ground at high (>3900 m; n = 19) and low (<120 m; n = 16) altitudes as well as under the ground at high (n = 20) and low (n = 16) altitudes. Participants’ heart rates, pulmonary functions, total energy expenditure and metabolism were measured over a 5-consecutive-day session at health clinics. (3) Results: Combining the results for both above- and underground locations, workers at high-altitude mining sites had significantly higher peak heart rate (HR), minimum average HR and training impulse as well as energy expenditure due to all substances and due to fat than those at low-altitude sites. They also had significantly higher uric acid, total cholesterol, creatine kinase and N-osteocalcin in their blood samples than the workers at low-altitude mining sites. At underground worksites, the participants working at high-altitude had a significantly higher average respiratory rate than those at low-altitude regions. (4) Conclusion: In addition to underground mining, attention should be paid to high-altitude mining as working under a hypoxia condition at such altitude likely presents physiological challenges.

Physical exercise is a powerful measure to prevent cardiometabolic diseases. However, the individual response to lifestyle interventions is variable and cannot, to date, be predicted. N-Lactoylphenylalanine (Lac-Phe) produced during exercise has recently been shown to mediate weight loss in obese mice. Lac-Phe could also contribute to, and potentially explain differences in, the effectiveness of exercise interventions in humans. Sedentary overweight and obese subjects completed an 8-week supervised endurance exercise intervention (n = 22). Before and after the intervention, plasma levels of Lac-Phe were determined by UHPLC-MS in the resting state and immediately after an acute bout of endurance exercise. Adipose tissue volume was quantified using MRI. Acute exercise caused a pronounced increase in Lac-Phe, both before and after the intervention. Higher levels of Lac-Phe after acute exercise were associated with a greater reduction in abdominal subcutaneous and, to a lower degree, visceral adipose tissue during the intervention. Lac-Phe produced during physical activity could contribute to weight loss by acting as a signaling molecule that regulates food intake, as previously shown in mice. Quantification of Lac-Phe during an exercise test could be employed as a tool to predict and potentially improve the individual response to exercise-based lifestyle interventions in overweight humans and those with obesity.

This study investigated the effect of high-intensity interval training (HIIT) cycling elevation training mask (ETM) in moderately trained participants on both aerobic (V̇O2max) and anaerobic power performance. Sixteen participants, five females (25.8 ± 7.6 years) and eleven males (22.2 ± 3.5 years) took part in this randomized controlled trial. Participants were assigned to the experimental group (ETM, n = 8 participants) wearing an ETM or the control group (CON, n = 8 participants) without the ETM. V̇O2max was determined during a standardized protocol using Cortex Metalyzer-3B on a cycle ergometer. Peak and average power were calculated a 30-second Wingate test. Participants completed 4-weeks (two sessions a week) of high-intensity cycle training. Each training session consisting of 4 separate bouts of 4-minutes of high-intensity cycling exercise. After the training period, ETM reported an increment in V̇O2max (effect size (d) = 1.19), peak power (d = 0.77), and average power (d = 0.76). CON reported an increment only in V̇O2max (d = 1.00). No-between group differences were found in any parameter (ANCOVA), therefore the two protocols should be considered equally effective. In conclusion, this study reported that both HIIT protocols significantly enhance V̇O2max in a very short training period (4 weeks).

Purpose: This study aimed to propose reference standards for cardiorespiratory fitness (CRF) for Brazil from a pooled analysis and to compare peak oxygen uptake (V˙o 2peak) in Brazilian, United States (US), and Norwegian samples, exploring possible national and international differences. Methods: Reference values for treadmill V˙o 2peak in three different Brazilian regions were assessed from previous publications. We analyzed available samples to assess possible differences, generate weighted average data for Brazil, and compared them with US and Norwegian data. Results: Brazilian reference values had a lower V˙o 2peak value for the Northeast region and a higher V˙o 2peak value for the Southeast region for all sex and age groups. International comparisons with the Brazilian pooled data (n = 26661) revealed higher values for the Norwegian sample (n = 3810) and lower values for the US sample (n = 16278). The observed heterogeneity in CRF is possibly related to differences in anthropometric (weight, height) and socioeconomic factors, which differed among the samples. Also, Brazilian data showed a curvilinear V˙o 2peak age reduction trend rather than the linear characteristic commonly utilized, and the regression curves were different from those for US and Norwegian data. Conclusion: This study provides new CRF reference standards for Brazil. After pooling data from three Brazilian regions, a comparison revealed notable differences between regions, evidencing a negative gradient from Southern to Northern regions. Similarly, the international comparisons between Brazil, US, and Norway data revealed CRF heterogeneity, with differences in the V˙o 2peak values and in the age relationship patterns. These findings reinforce the importance of using national- or regional-specific V˙o 2peak reference values, ensuring proper CRF evaluation.

Objective Portable gas exchange instruments allow the assessment of peak oxygen uptake (V̇O2peak) but are often bulky, expensive and require wearing a face mask thereby limiting their routine application. A newly developed miniaturized headset (VitaScale, Nuremberg, Germany) may overcome these barriers and allow measuring V̇O2peak without applying a face mask. Here we aimed (i) to disclose the technical setup of a headset incorporating a gas and volume sensor to measure volume flow and expired oxygen concentration and (ii) to assess the concurrent criterion-validity of the headset to measure V̇O2peak in 44 individuals exercising on a stationary cycle ergometer in consideration of the test–retest reliability of the criterion measure. Results The coefficient of variation (CV%) while measuring V̇O2peak during incremental cycling with the headset was 6.8%. The CV% for reliability of the criterion measure was 4.0% for V̇O2peak. Based on the present data, the headset might offer a new technology for V̇O2peak measurement due to its low-cost and mask-free design.

Since the beginning of the SARS‐CoV‐2 pandemic, the community use of facemasks has been widely recommended. However, their use during exercise has raised safety concerns. Thus, we compared the physiological differences between exercising wearing a surgical (SM) or a double‐layer‐cotton (DLC) facemask and not wearing a mask (NM). Sixteen volunteers underwent 4 bouts of cycling‐based exercise, which consisted of two different intensities: light‐to‐moderate and moderate‐to‐high. Facemasks were used as follows: bout‐1 and 4: NM; bout‐2: SM or DLC and bout‐3: DLC or SM. Ventilatory, metabolic, pulmonary gas exchange (PGE) and perceptual variables were collected. At both exercise intensities compared to NM, both facemasks induced similar ventilatory adaptations, increasing inspiratory time and tidal volume and decreasing breathing frequency. Effect sizes (ES) were larger for DLC than for SM. At moderate‐to‐high, both facemasks reduced the minute ventilation, whereas at light‐to‐moderate, it was only seen with DLC. End tidal and mixed CO 2 pressures, as well as the difference between them, increased with both facemasks. Again, ES was larger for DLC than SM. No relevant oxygen saturation drop was observed with both facemaks and exercise intensities. A small ES increament in VO 2 and VCO 2 were seen with both facemasks. Effort perception increased at moderate‐to‐high for both exercise intensities, buth larger EF were with DLC than SM. DLC increased facial temperature during both exercise intensities. In conclusion, ventilatory adjustments imposed during facemask exercise influenced PGE and metabolic and perceptual changes. Larger ES were mostly seen for DLC than SM. Abbreviations: B f : Breathing frequency.; CPET: Cardiopulmonary exercise test.; CI: Confidence interval.; DLC: Double‐layer cotton.; E T CO 2 : End tidal CO 2 pressure.; ES: Effect size.; ΔE T ‐PECO 2 : Difference between E T CO 2 and PECO 2. ; FMMT: Facemask microclimate temperature.; H R : Heart rate.; IQR: Interquartile range.; NM: No mask.; PECO 2 : Mixed‐expired CO 2 pressure.; RER: Respiratory exchange ratio.; RPE: Rate of perceived effort.; SD: Standard deviation.; SM: Surgical Mask.; SpO 2 : Oxygen saturation.; STP: Subjective thermal perception.; T i /T TOT : Duty cycle.; V E : Minute ventilation.; VCO 2 : Carbon dioxide output.; VO 2 : Oxygen uptake.; V T : Tidal volume.; VT: Ventilatory threshold. Highlights Facemasks affect the breathing pattern by changing the frequency and amplitude of pulmonary ventilation. The augmented ventilatory work increases VO 2 , VCO 2 , and RPE and promotes nonconcerning drops in SpO 2 and CO 2 retention. Increased inspiratory and expiratory pressure can account for the reduction in pulmonary physiological dead space.

Purpose Cardiopulmonary exercise testing (CPET) in preschoolers (4–6 years) represents a challenge. Most studies investigating CPET have been limited to older children (> 8 year). However, knowledge of the performance of small children is essential for evaluating their cardiorespiratory fitness. This study strives to compare a modified Bruce protocol with a new age-appropriate incremental CPET during natural movement running outdoors, using a mobile device. Methods A group of 22 4–6-year-old healthy children was tested indoor on a treadmill (TM) using the modified Bruce protocol. The results were compared with a self-paced incremental running test, using a mobile CPET device in an outdoor park. The speeds were described as (1) slow walking, (2) slow running, (3) regular running, and (4) running with full speed as long as possible. Results Mean exercise time outdoors (6,57 min) was significantly shorter than on the treadmill (11,20 min), V̇O_2peak V ˙ O 2 p e a k (51.1 ml/min/kg vs. 40.1 ml/min/kg), RER (1.1 vs. 0.98) and important CPET parameters such as V̇E V ˙ E max, O2pulse, heart rate and breath rate were significantly higher outdoors. The submaximal parameter OUES was comparable between both the tests. Conclusions Testing very young children with a mobile device is a new alternative to treadmill testing. With a significantly shorter test duration, significantly higher values for almost all cardiopulmonary variables can be achieved without losing the ability to determine VT1 and VT2. It avoids common treadmill problems and allows for individualized exercise testing. The aim is to standardize exercise times with individual protocols instead of standardizing protocols with individual exercise times, allowing for better comparability.

Background In a sprint cross-country (XC) ski competition, the difference in recovery times separating the first and the second semi-final (SF) heats from the final (F) may affect performance. The aim of the current study was to compare the effects of longer vs. shorter recovery periods prescribed between the 3 knock-out races of a simulated sprint XC ski competition involving a prologue (P), quarter-final (QF), SF, and F. Methods Eleven well-trained XC ski athletes completed 2 simulated sprint XC ski competitions on a treadmill involving 4 × 883-m roller-ski bouts at a 4° incline using the gear 3 ski-skating sub-technique. The first 3 bouts were completed at a fixed speed (PFIX, QFFIX, and SFFIX) corresponding to ∼96% of each individual's previously determined maximal effort. The final bout was performed as a self-paced sprint time trial (FSTT). Test conditions differed by the time durations prescribed between the QFFIX, SFFIX, and FSTT, which simulated real-world XC ski competition conditions using maximum (MAX-REC) or minimum (MIN-REC) recovery periods. Results The FSTT was completed 5.4 ± 5.5 s faster (p = 0.009) during MAX-REC (179.2 ± 18.1 s) compared to MIN-REC (184.6 ± 20.0 s), and this was linked to a significantly higher power output (p = 0.010) and total metabolic rate (p = 0.009). The pre FSTT blood lactate (BLa) concentration was significantly lower during MAX-REC compared to MIN-REC (2.5 ± 0.8 mmol/L vs. 3.6 ± 1.6 mmol/L, respectively; p = 0.027), and the pre-to-post FSTT increase in BLa was greater (8.8 ± 2.1 mmol/L vs. 7.1 ± 2.3 mmol/L, respectively; p = 0.024). No other differences for MAX-REC vs. MIN-REC reached significance (p > 0.05). Conclusion Performance in a group of well-trained XC skiers is negatively affected when recovery times between sprint heats are minimized which, in competition conditions, would occur when selecting the last QF heat. This result is combined with a higher pre-race BLa concentration and a reduced rise in BLa concentration under shorter recovery conditions. These findings may help inform decision making when XC skiers are faced with selecting a QF heat within a sprint competition.

Purpose: Although sport climbing is a self-paced whole-body activity, speed varies with climbing style, and the effect of this on systemic and localized oxygen responses is not well understood. Therefore, the aim of the present study was to determine muscle and pulmonary oxygen responses during submaximal climbing at differing speeds of ascent. Methods: Thirty-two intermediate and advanced sport climbers completed three 4-minute-long ascents of the same route at 4, 6, and 9 m·min−1 on a motorized climbing ergometer (treadwall) on separate laboratory visits. Gas analysis and near-infrared spectroscopy were used to determine systemic oxygen uptake () and muscle oxygen saturation (StO2) of the flexor digitorum profundus. Results: Increases in ascent speed of 1 m·min−1 led to increases of by 2.4 mL·kg−1·min−1 (95% CI, 2.1 to 2.8 mL·kg−1·min−1) and decreases in StO2 by −1.3% (95% CI, 1.9% to −0.7%). There was a significant interaction of climbing ability and speed for StO2 (P < .001, ). The results revealed that the decrease of StO2 was present for intermediate but not advanced climbers. Conclusions: In this study, the results suggest that demand during climbing was largely determined by climbing speed; however, the ability level of the climber appeared to mitigate StO2 at a cellular level. Coaches and instructors may prescribe climbing ascents with elevated speed to improve generalized cardiorespiratory fitness. To stimulate localized aerobic capacity, however, climbers should perhaps increase the intensity of training ascents through the manipulation of wall angle or reduction of hold size.

Purpose Kinetics of cardiorespiratory parameters (CRP) in response to work rate (WR) changes are evaluated by pseudo-random binary sequences (PRBS testing). In this study, two algorithms were applied to convert responses from PRBS testing into appropriate impulse responses to predict steady states values and responses to incremental increases in exercise intensity. Methods 13 individuals (age: 41 ± 9 years, BMI: 23.8 ± 3.7 kg m−2), completing an exercise test protocol, comprising a section of randomized changes of 30 W and 80 W (PRBS), two phases of constant WR at 30 W and 80 W and incremental WR until subjective fatigue, were included in the analysis. Ventilation (V̇_E V ˙ E ), O2 uptake (V̇O_2 V ˙ O 2 ), CO2 output (V̇CO_2 V ˙ CO 2 ) and heart rate (HR) were monitored. Impulse responses were calculated in the time domain and in the frequency domain from the cross-correlations of WR and the respective CRP. Results The algorithm in the time domain allows better prediction for V̇O_2 V ˙ O 2 and V̇CO_2 V ˙ CO 2 , whereas for V̇_E V ˙ E and HR the results were similar for both algorithms. Best predictions were found for V̇O_2 V ˙ O 2 and HR with higher (3–4%) 30 W steady states and lower (1–4%) values for 80 W. Tendencies were found in the residuals between predicted and measured data. Conclusion The CRP kinetics, resulting from PRBS testing, are qualified to assess steady states within the applied WR range. Below the ventilatory threshold, V̇O_2 V ˙ O 2 and HR responses to incrementally increasing exercise intensities can be sufficiently predicted.

Significance Airborne transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) or other pathogens is probably increased during indoor exercise, but data on the emission of aerosol particles by an exercising individual are lacking. Here, we report that aerosol particle emission increases on average 132-fold from 580 ± 489 particles/min at rest to 76,200 ± 48,000 particles/min during maximal exercise. Aerosol particle emission increases moderately up to an exercise intensity of ≈2 W/kg and exponentially at higher exercise intensities. These data not only explain SARS-CoV-2 transmissions during indoor group exercise but also can be used to design better targeted mitigation measures for physical activity indoors such as physical education in school, dance events during weddings, or high-intensity gym classes such as spinning.

The multisystem impairment promoted by COVID‐19 may be associated with a reduction in exercise capacity. Cardiopulmonary abnormalities can change across the acute disease severity spectrum. We aimed to verify exercise physiology differences between COVID‐19 survivors and SARS‐CoV‐2‐naïve controls and how illness severity influences exercise limitation. A single‐centre cross‐sectional analysis of prospectively collected data from COVID‐19 survivors who underwent cardiopulmonary exercise testing (CPET) in their recovery phase (x = 50[36;72] days). Patients with COVID‐19 were stratified according to severity as mild [M‐Cov (outpatient)] vs severe/critical [SC‐Cov(inpatients)] and were compared with SARS‐CoV‐2‐naïve controls (N‐Cov). Collected information included demographics, anthropometrics, previous physical exercise, comorbidities, lung function test and CPET parameters. A multivariate logistic regression analysis was performed to identify low aerobic capacity (LAC) predictors post COVID‐19. Of the 702 included patients, 310 (44.2%), 305 (43.4%) and 87 (12.4%) were N‐Cov, M‐Cov and SC‐Cov, respectively. LAC was identified in 115 (37.1%), 102 (33.4%), and 66 (75.9%) of N‐CoV, M‐CoV and SC‐CoV, respectively (p < 0.001). SC‐Cov were older, heavier with higher body fat, more sedentary lifestyle, more hypertension and diabetes, lower forced vital capacity, higher prevalence of early anaerobiosis, ventilatory inefficiency and exercise‐induced hypoxia than N‐Cov. M‐Cov had lower weight, fat mass, and coronary disease prevalence and did not demonstrate more CEPT abnormalities than N‐Cov. After adjustment for covariates, SC‐Cov was an independent predictor of LAC (OR = 2.7; 95% CI, 1.3‐5.6). Almost two months after disease onset, SC‐CoV presented several exercise abnormalities of oxygen uptake, ventilatory adaptation and gas exchange, including a high prevalence of LAC. Highlights Weeks after the acute disease phase, one‐third of mild and three‐quarters of severe and critical patients with COVID‐19 presented a reduced aerobic capacity. Previous studies including SARS‐CoV‐1 survivors observed much lower values. A severe or critical COVID‐19 case was an independent predictor for low aerobic capacity. In our sample, pre‐COVID‐19 exercise significantly reduced the odds of post‐COVID‐19 low aerobic capacity. Even severe or critical patients who exercised regularly had a prevalence of low aerobic capacity 2.5 times lower than those who did not have this routine before sickening.

Zusammenfassung Wearable Devices versprechen durch ihre motivierende Wirkung einen wichtigen Beitrag zur Bindung des Individuums an körperlich-sportliche Aktivitäten und somit zum Aufbau und Erhalt von Gesundheit und Leistungsfähigkeit in Zeiten des digitalen gesellschaftlichen Wandels. Übergeordnetes Ziel der vorliegenden Untersuchung war die Beurteilung der Testgüte von Wearable Devices anhand eines marktrelevanten Gerätes, der Garmin fēnix® 5. Als Forschungsdesiderat wurde der Reliabilitätsaspekt der Methodenkonkordanz identifiziert. Zur Überprüfung der Methodenkonkordanz wurden das Stresslevel bei kognitiver Stressinduktion, der Kalorienverbrauch bei moderater Ausdauerlaufbelastung sowie die maximale Sauerstoffaufnahme bei Laufausbelastung von 30 männlichen Probanden (Alter: 23,13 ± 2,5 Jahre; BMI: 24,95 ± 2,45 kg/m2) mit der Garmin fēnix® 5 bestimmt und die Ergebnisse mit denen im Feld gängigen Referenzmethoden Elektrokardiographie, Indirekte Kalorimetrie bzw. Spiroergometrie verglichen. Zur rechnerischen Überprüfung der Methodenkonkordanz diente Lin’s Konkordanzkorrelationskoeffizient (CCCLin). Die Ergebnisse zeigen eine hohe Präzision der Garmin fēnix® 5 im Vergleich mit der Referenzmethode Elektrokardiographie hinsichtlich der Messung des notwendigerweise z-standardisierten Stressparameters (p = 0,89) sowie eine gerade mittlere exakte intrainidividuelle Konkordanz mit der Referenzmethode Indirekte Kalorimetrie bzw. Spiroergometrie hinsichtlich der Messung des Parameters Kalorienverbrauch (CCCLin = 0,43 [p = 0,52, Cb = 0,82]) bzw. maximale Sauerstoffaufnahme (CCCLin = 0,50 [p = 0,77, Cb = 0,66]). Die Garmin fēnix® 5 kann somit zumindest bei erstmaliger Verwendung nicht als hinreichend konkordante Alternative zu den gängigen aktivitäts- und leistungsbezogenen Referenzmethoden empfohlen werden.

Introduction Adequate cardiorespiratory fitness is of utmost importance during spaceflight and should be assessable via moderate work rate intensities, e.g., using kinetics parameters. The combination of restricted sleep, and defined physical exercise during a 45-day simulated space mission is expected to slow heart rate (HR) kinetics without changes in oxygen uptake (VO_2 V ˙ O 2 ) kinetics. Methods Overall, 14 crew members (9 males, 5 females, 37 ± 7 yrs, 23.4 ± 3.5 kg m−2) simulated a 45-d-mission to an asteroid. During the mission, the sleep schedule included 5 nights of 5 h and 2 nights of 8 h sleep. The crew members were tested on a cycle ergometer, using pseudo-random binary sequences, changing between 30 and 80 W on day 8 before (MD-8), day 22 (MD22) and 42 (MD42) after the beginning and day 4 (MD + 4) following the end of the mission. Kinetics information was assessed using the maxima of cross-correlation functions (CCFmax). Higher CCFmax indicates faster responses. Results CCFmax(HR) was significantly (p = 0.008) slower at MD-8 (0.30 ± 0.06) compared with MD22 (0.36 ± 0.06), MD42 (0.38 ± 0.06) and MD + 4 (0.35 ± 0.06). Mean HR values during the different work rate steps were higher at MD-8 and MD + 4 compared to MD22 and MD42 (p < 0.001). Discussion The physical training during the mission accelerated HR kinetics, but had no impact on mean HR values post mission. Thus, HR kinetics seem to be sensitive to changes in cardiorespiratory fitness and may be a valuable parameter to monitor fitness. Kinetics and capacities adapt independently in response to confinement in combination with defined physical activity and sleep.

Reliable monitoring of one’s response to exercise intensity is imperative to effectively plan and manage training, but not always practical in impact sports settings. This study aimed to evaluate if an inexpensive mobile cardio-respiratory monitoring system can achieve similar performance to a metabolic cart in estimating rated perceived exertion. Eight adult men volunteered to perform treadmill tests under different conditions. Cardiorespiratory data were collected using a metabolic cart and an instrumented oral-cavity device, as well as their ratings of perceived exertion. Pearson correlation corrected for repeated measurements and stepwise regression analysis were used to observe the relationship between the cardiorespiratory features and the ratings of perceived exertion and determine the proportion of the variance of exertion that could be explained by the measurements. Minute ventilation was found to be the most associated variable to perceived exertion, closely followed by a novel metric called the audio minute volume, which can be collected by the oral-cavity device. A generalised linear model combining minute ventilation, audio minute volume, heart rate and respiration rate accounted for 64% of the variance in perceived exertion, whilst a model with only audio minute volume accounted for 56%. Our study indicates that minute ventilation is key to estimating perceived exertion during indoor running exercises. Audio minute volume was also observed to perform comparably to a lab-based metabolic cart in estimating perceived exertion. This research indicates that mobile techniques offer the potential for real-world data collection of an athlete’s physiological load and estimation of perceived exertion.

While swimming represents a popular recreational activity, the immersion of the human body into the water requires a complex physiologic adaption of the whole cardiopulmonary and circulatory system. While this sport is regarded as beneficial, especially in cardiovascular patients, current guidelines hypothesized a possible hazardous effect of swimming and especially diving in patients with univentricular hearts after Fontan palliation. Yet, actual data to underline or contradict these assumptions are lacking. Therefore, this study aimed to conduct a first feasibility study for the evaluation of these effects on Fontan physiology and elucidate the gap of evidence currently preventing patients after Fontan palliation from being restricted from swimming or diving on doctoral advice. Patients recruited from the Heart Center Leipzig, Department of pediatric cardiology, underwent spiroergometry treadmill testing followed by a spiroergometry swimming stress test in a counter current pool. Physiologic data were recorded. A short apnea diving test was performed. The current study found similar physiologic reactions comparing treadmill and swimming exercise stress testing. Heart rate response and oxygen uptake were comparable on land and in the water. This study presents the first-in-man data on swimming and diving in Fontan patients. In this small study cohort of three Fontan patients, there were no adverse events triggered by swimming and breath-hold diving seen. Basically, the physiologic response to exercise was comparable on land and in the water.

Oxygen consumption (\,VO_2 V ̇ O 2 ) provides established clinical and physiological indicators of cardiorespiratory function and exercise capacity. However, \,VO_2 V ̇ O 2 monitoring is largely limited to specialized laboratory settings, making its widespread monitoring elusive. Here we investigate temporal prediction of \,VO_2 V ̇ O 2 from wearable sensors during cycle ergometer exercise using a temporal convolutional network (TCN). Cardiorespiratory signals were acquired from a smart shirt with integrated textile sensors alongside ground-truth \,VO_2 V ̇ O 2 from a metabolic system on 22 young healthy adults. Participants performed one ramp-incremental and three pseudorandom binary sequence exercise protocols to assess a range of \,VO_2 V ̇ O 2 dynamics. A TCN model was developed using causal convolutions across an effective history length to model the time-dependent nature of \,VO_2 V ̇ O 2 . Optimal history length was determined through minimum validation loss across hyperparameter values. The best performing model encoded 218 s history length (TCN-VO2 A), with 187, 97, and 76 s yielding <3% deviation from the optimal validation loss. TCN-VO2 A showed strong prediction accuracy (mean, 95% CI) across all exercise intensities (−22 ml min−1, [−262, 218]), spanning transitions from low–moderate (−23 ml min−1, [−250, 204]), low–high (14 ml min−1, [−252, 280]), ventilatory threshold–high (−49 ml min−1, [−274, 176]), and maximal (−32 ml min−1, [−261, 197]) exercise. Second-by-second classification of physical activity across 16,090 s of predicted \,VO_2 V ̇ O 2 was able to discern between vigorous, moderate, and light activity with high accuracy (94.1%). This system enables quantitative aerobic activity monitoring in non-laboratory settings, when combined with tidal volume and heart rate reserve calibration, across a range of exercise intensities using wearable sensors for monitoring exercise prescription adherence and personal fitness.

Purpose The aims of this study were (1) to investigate if the respiratory compensation point (RCP) as derived from ramp incremental (RI) exercise could accurately predict the power output (PO) at the maximal lactate steady state (MLSS), and (2) to compare its accuracy with the second lactate threshold (LT2) obtained from step incremental (SI) exercise. Methods Nineteen participants performed a RI test (30 W·min-1) to determine RCP, a SI test (30 or 40 W·3 min-1) to determine LT2, and two or more constant work rate (CWR) tests to determine MLSS. For each participant, the [Formula: see text]O2/PO relationship for RI and CWR exercise was established. The ramp-identified PO at RCP was corrected by accounting for the gap between these relationships using the individually determined [Formula: see text] O2/PO regression above GET (RCPcorr-1) or using a fixed regression slope (RCPcorr-2). LT2 was determined using four methods: Dmax, modified Dmax (ModDmax), 4-mM threshold (LT4mM) and an expert-determined LT2 (LT2-expert). Results RCPcorr-1 (235 ± 69 W), RCPcorr-2 (228 ± 58 W) and LT2-expert (227 ± 61 W) were not different from MLSS (225 ± 60 W). Dmax (203 ± 53 W) underestimated MLSS, while RCP (280 ± 60 W), ModDmax (235 ± 67 W) and LT4mM (234 ± 68 W) overestimated MLSS. The [Formula: see text]O2 at RCP (3.13 ± 0.79L·min-1) and LT2-expert (2.99 ± 0.19L·min-1) did not differ from MLSS (3.05 ± 0.72 L·min-1). Conclusion This study demonstrated that RCP as derived from RI exercise and LT2 as derived from SI exercise can be equally accurate to determine the PO associated with MLSS. Although these results confirmed the suitability of RI and SI tests for this purpose, they also highlighted the importance of an appropriate threshold method selection and the eye of the expert.

The purpose of the study was to compare the psychophysiological response of climbers of a range of abilities (lower grade to advanced) when ascending identical climbing routes on a climbing wall and a rotating treadwall. Twenty-two female climbers (31.2 ± 9.4 years; 60.5 ± 6.5 kg; 168.6 ± 5.7 cm) completed two identical 18 m climbing trials (graded 4 on the French Sport scale) separated by 1 week, one on the treadwall (climbing low to the ground) and the other on the indoor wall (climbing in height). Indirect calorimetry, venous blood samples and video-analysis were used to assess energy cost, hormonal response and time-load characteristics. Energy costs were higher during indoor wall climbing comparing to those on the treadwall by 16% (P < 0.001, _p^2 μ p 2  = 0.48). No interaction of climbing ability and climbing condition were found. However, there was an interaction for climbing ability and post-climbing catecholamine concentration (P < 0.01, _p^2 μ p 2  = 0.28). Advanced climbers’ catecholamine response increased by 238% and 166% with respect to pre-climb values on the treadwall and indoor wall, respectively; while lower grade climbers pre-climb concentrations were elevated by 281% and 376% on the treadwall and indoor wall, respectively. The video analysis showed no differences in any time-motion variables between treadwall and indoor wall climbing. The study demonstrated a greater metabolic response for indoor wall climbing, however, the exact mechanisms are not yet fully understood.

Purpose Sport climbing requires high-intensity finger flexor contractions, along with a substantial whole-body systemic oxygen uptake ([Formula: see text]O2) contribution. Although fatigue is often localised to the finger flexors, the role of systemic ̇[Formula: see text]O2 and local aerobic mechanisms in climbing performance remains unclear. As such, the primary purpose of this study was to determine systemic and local muscle oxygen responses during both isolated finger flexion and incremental exhaustive whole-body climbing tests. The secondary aim was to determine the relationship of isolated and whole-body climbing endurance tests to climbing ability. Methods Twenty-two male sport climbers completed a series of isometric sustained and intermittent forearm flexor contractions, and an exhaustive climbing test with progressive steepening of the wall angle on a motorised climbing ergometer. Systemic [Formula: see text]O2 and flexor digitorum profundus oxygen saturation (StO2) were recorded using portable metabolic analyser and near-infra red spectroscopy, respectively. Results Muscle oxygenation breakpoint (MOB) was identifiable during an incremental exhaustive climbing test with progressive increases in angle (82 ± 8% and 88 ± 8% [Formula: see text]O2 and heart rate climbing peak). The peak angle from whole-body treadwall test and impulse from isolated hangboard endurance tests were interrelated (R2 = 0.58-0.64). Peak climbing angle together with mean [Formula: see text]O2 and StO2 from submaximal climbing explained 83% of variance in self-reported climbing ability. Conclusions Both systemic and muscle oxygen kinetics determine climbing-specific endurance. Exhaustive climbing and isolated finger flexion endurance tests are interrelated and suitable to assess climbing-specific endurance. An exhaustive climbing test with progressive wall angle allows determination of the MOB.

Background Chronotropic incompetence has shown to be associated with a decrease in exercise capacity in heart failure with preserved ejection fraction (HFpEF), yet β-blockers are commonly used in HFpEF despite the lack of robust evidence. Objectives This study aimed to evaluate the effect of β-blocker withdrawal on peak oxygen consumption (peak Vo2) in patients with HFpEF and chronotropic incompetence. Methods This is a multicenter, randomized, investigator-blinded, crossover clinical trial consisting of 2 treatment periods of 2 weeks separated by a washout period of 2 weeks. Patients with stable HFpEF, New York Heart Association functional classes II and III, previous treatment with β-blockers, and chronotropic incompetence were first randomized to withdrawing from (arm A: n = 26) versus continuing (arm B: n = 26) β-blocker treatment and were then crossed over to receive the opposite intervention. Changes in peak Vo2 and percentage of predicted peak Vo2 (peak Vo2%) measured at the end of the trial were the primary outcome measures. To account for the paired-data nature of this crossover trial, linear mixed regression analysis was used. Results The mean age was 72.6 ± 13.1 years, and most of the patients were women (59.6%) in New York Heart Association functional class II (66.7%). The mean peakVo2 and peak Vo2% were 12.4 ± 2.9 mL/kg/min, and 72.4 ± 17.8%, respectively. No significant baseline differences were found across treatment arms. Peak Vo2 and peak Vo2% increased significantly after β-blocker withdrawal (14.3 vs 12.2 mL/kg/min [Δ +2.1 mL/kg/min]; P < 0.001 and 81.1 vs 69.4% [Δ +11.7%]; P < 0.001, respectively). Conclusions β-blocker withdrawal improved maximal functional capacity in patients with HFpEF and chronotropic incompetence. β-blocker use in HFpEF deserves profound re-evaluation. (β-blockers Withdrawal in Patients With HFpEF and Chronotropic Incompetence: Effect on Functional Capacity [PRESERVE-HR]; NCT03871803; 2017-005077-39).

Background Cardiorespiratory fitness is often impaired following stroke, and peak oxygen consumption (VO2peak) is an important prognostic value of all-cause mortality. The primary objective was to investigate whether functional walk tests assessed in the subacute phase after stroke added value in predicting VO2peak in chronic stroke, in addition to age, sex and functional dependency. Secondary objectives were to investigate associations between daily physical activity and functional walk tests, and with VO2peak in chronic stroke. Methods This prospective cohort study included eligible participants originally included in the randomized controlled trial Life After Stroke. Functional walk tests, i.e., six-minute walk test (6MWT) and maximal gait speed, were assessed at inclusion and 18 months later. VO2peak [ml/kg/min] was assessed by a cardiopulmonary exercise test on a treadmill 20 months after inclusion. Daily physical activity was measured by a uniaxial accelerometer (activPAL) at 18-month follow-up. Results Ninety-two community-dwelling individuals, with a mean (SD) age of 69.2 (10.6) years and 33 (35.9%) women, were included 3 months after stroke onset. Eighty-three (90.2%) participants had a modified Rankin Scale (mRS) score of 1 or 2, indicating functional independence. An overall assessment of four prediction models indicated the combination of age, sex, mRS and 6MWT as predictors to be the best fitted model in predicting VO2peak (adjusted R2 = 0.612). Secondary results showed statistically significant, but not clinically significant, associations between daily physical activity and functional walk tests, and with VO2peak. Conclusions 6MWT add significant value to the prediction of mean VO2peak in the chronic phase in mild strokes, in combination with age, sex and functional dependency. This prediction model may facilitate clinical decisions and rehabilitation strategies for mildly affected stroke survivors in risk of low levels of VO2peak. Future studies should validate the model in various stages after stroke and in patients moderately and severely affected.

The purpose of the work was to characterize the 4-year preparation cycle for the Winter Olympic Games in Pyongyang (2018), the leading Polish speed skater M.W. Longitudinal tests included assessment of aerobic and anaerobic exercise capacity determined in laboratory tests, respectively in the graded bicycle ergometer test and in the Wingate test performed with the lower extremity. The longitudinal data from exercise tests obtained in the analyzed 4-year period of preparation for the Olympic Games clearly indicate a significant improvement in the skater's exercise capacity. In the examined period of 2015-2018, the athlete obtained an increase in VO2max value by 6.5% to the level of 55.8 ml/kg/min. The nature of the observed changes in selected exercise indicators corresponded to the assumptions and implementation of training plans. The examined athlete was very well prepared for qualifying starts in October-November 2017 and she won three Olympic qualifications at distances 500, 1000 and 1500 m. During the Olympic Games, the Polish representative started the competition with starts at distances 1500 (20th place) and 500 m (28th place). At the leading distance of 1000 m, the competitor started at her level, reaching 12th place thus fulfilling the pre-start assumptions.

Background Recent studies reported that wearable sensor devices show low validity for assessing the amount of energy expenditure in individuals after stroke. Objective We aimed to evaluate the validity of energy expenditure calculation based on the product of energy cost and walked distance estimated by wearable devices in individuals after hemispheric stroke. Methods We recruited individuals with hemispheric stroke sequelae who were able to walk without human assistance. The participants wore a tri-axial accelerometer (Actigraph GT3x) and a pedometer (ONStep 400) on the unaffected hip in addition to a respiratory gas exchange analyzer (METAMAX 3B) during 6min of walking at their self-selected walking speed and mode. The energy expenditure was calculated from the product of energy cost measured by the METAMAX 3B and the distance estimated by wearable devices. It was compared to the energy expenditure measured by the METAMAX 3B and the energy expenditure values recorded by the devices according to the manufacturer's algorithms. The validity was investigated by Bland-Altman analysis (mean bias [MB], root mean square error [RMSE], limits of agreement [95%LoA]), and Pearson correlation analysis (r). Results We included 26 participants (mean [SD] age 64.6 [14.8] years). With the pedometer, the energy expenditure calculated from the product of energy cost and walked distance showed high accuracy and agreement with METAMAX 3B values (MB=-1.6kcal; RMSE=4.1kcal; 95%LoA=-9.9; 6.6kcal; r=0.87, P<0.01) but low accuracy and agreement with Actigraph GT3x values (MB=15.7kcal; RMSE=8.7kcal; 95%LoA=-1.3; 32.6kcal; r=0.44, P=0.02) because of poorer estimation of walked distance. With the pedometer, this new method of calculation strongly increased the validity parameter values for estimating energy expenditure as compared with the manufacturer's algorithm. Conclusions This new method based on the energy cost and distance estimated by wearable devices provided better energy expenditure estimates for the pedometer than did the manufacturer's algorithm. The validity of this method depended on the accuracy of the sensor to measure the distance walked by an individual after stroke.

Background/purpose We aimed to investigate the efficacy of cardiac rehabilitation (CR) through parameters of cardiopulmonary exercise testing (CPET) and echocardiography in non-ischemic dilated cardiomyopathy (DCM) patients. Methods We retrospectively identified non-ischemic DCM patients through medical records (between October 2011 and October 2018) in rehabilitation outpatient-clinics. Patients were divided into rehabilitation and control groups. Patients in the rehabilitation group eligible for inclusion had CR for 3-6 months. Control group patients were without rehabilitation. We recorded CPET and echocardiography parameters at the baseline and follow-up time-points. For safety evaluation, we investigated all adverse effects during training sessions. We utilized Mann-Whitney U test for between- and Wilcoxon signed-rank test for within-group comparisons. Results Twenty-five patients (14 in rehabilitation and 11 in control group) were included. In the rehabilitation group, significantly increased peak V˙O2/kg, peak V˙O2%, peak workload and peak O2 pulse were observed after completing CR, and echocardiographic parameters including left ventricular ejection fraction and end-systolic volume. Rehabilitation group patients demonstrated better improvement (change from the baseline) in peak V˙O2/kg, peak V˙O2% and peak workload vs. control. No adverse effects during rehabilitation trainings were observed. Conclusion For non-ischemic DCM, rehabilitation led to superior cardiopulmonary outcomes vs. no rehabilitation, without adverse effects.

Purpose To test whether the oxygen uptake ([Formula: see text]) plateau at [Formula: see text] is simply a calculation artifact caused by the variability of [Formula: see text] or a clearly identifiable physiological event. Methods Forty-six male participants performed an incremental ramp and a [Formula: see text] verification test. Variability of the difference between adjacent sampling intervals (difference) and of the slope of the [Formula: see text]-workload relationship (slope) in the submaximal intensity domain were calculated. Workload defined sampling intervals used for the calculation of the difference and slope were systematically increased from 20 to 100 W until the expected risk of false plateau diagnoses based on the Gaussian distribution function was lower than 5%. Overall, more than 1500 differences and slopes were analyzed. Subsequently, frequencies of plateau diagnoses in the submaximal and maximal intensity domains were compared. Results Variability of the difference and slope decreased with increasing sampling interval (p < 0.001). At a sampling interval of 50 W, the predefined acceptable risk of false plateau diagnoses (≤ 5%) was achieved. At this sampling interval, the actual frequency (1.4%) of false-positive plateau diagnoses did not differ from the expected frequency in the submaximal intensity domain (1.6%; p = 0.491). In contrast, the actual frequency at maximal intensity (35.7%) was significantly higher compared to the submaximal intensity domain (p < 0.001) and even higher than the expected frequency of false-positive diagnoses (p < 0.001). Conclusion The [Formula: see text] plateau at [Formula: see text] represents a physiological event and no calculation artifact caused by [Formula: see text] variability. However, detecting a [Formula: see text] plateau with sufficient certainty requires large sampling intervals.

Mean normalized gain is able to detect differences in V̇O2p kinetics between moderate-, heavy-, and heavy-intensity exercises from a raised WR within the same individuals. This new method of kinetic analysis may be advantageous compared with conventional curve fitting, as it is less sensitive to breath-by-breath noise, it can provide useful information from a single exercise testing session, and it can be applied to nonconstant work rate exercise situations.

Based on the wide range of problems to effectively perform cardiopulmonary testing in young children, this study strives to develop a new cardiopulmonary exercise test for children using a mobile testing device worn in a backpack in order to test children during their natural movement habits, namely, running outdoors. A standard cardiopulmonary exercise ramp test on a cycle ergometer was performed by a group of twenty 7–10-year-old children. The results were compared with a self-paced incremental running test performed using a mobile cardiopulmonary exercise measuring device in an outdoor park. The children were able to reach significantly higher values for most of the cardiopulmonary exercise variables during the outdoor test and higher. Whereas a plateau inVO_2V˙O2was reached by 25% of the children during the outdoor test, only 75% were able to reach a reasonable VT2, let aloneVO_2peakV˙O2peak, during the bicycle test. The heart rate at VT1, the O2-pulse, and the OUES were comparable between both tests. OUES was also positively correlated withVO_2peakV˙O2peakin both tests. Testing children outdoors using a mobile cardiopulmonary exercise unit represents an alternative to standard exercise testing, but without the added problems of exercise equipment like treadmills or bicycles. It allows for individualized exercise testing with the aim of standardized testing durations instead of standardized testing protocols. The running speeds determined during the outdoor tests may then be used to develop age-adapted testing protocols for treadmill testing.

Bottollier, V, Coulmy, N, Le Quellec, L, and Prioux, J. Energy demands in well-trained alpine ski racers during different duration of slalom and giant slalom runs. J Strength Cond Res 34(8): 2156–2164, 2020—The purpose of this study was to investigate the energy demands of different duration slalom (SL) and giant slalom (GS) events in well-trained alpine ski racers. Eight well-trained alpine ski racers (age: 18.2 ± 0.8 years; stature: 1.72 ± 0.10 m; body mass: 65.8 ± 12.0 kg) performed an incremental laboratory test on cycle ergometer and 4 standardized alpine ski runs: short (ST) and long (LG) versions of SL and GS (SLST, SLLG, GSST, and GSLG). Oxygen uptake (V̇o 2) and heart rate (HR) were recorded continuously in all conditions. Blood lactate ([La]) was determined immediately before run and 3 and 5 minutes after run ([La]peak). The contribution of aerobic, glycolytic, and phosphagen energy systems was estimated. The aerobic system was the primary energy system involved in GSST (43.9 ± 5.7%) and GSLG (48.5 ± 2.5%). No significant difference in the contribution of aerobic and glycolytic systems was observed in SLST and SLLG. [La]peak was higher in SLLG (11.10 ± 2.41 mmol·L−1) than in GSST (8.01 ± 2.01 mmol·L−1). There was no difference in oxygen uptake peak between GSST and GSLG. Energetic training goals should focus on the improvement of both aerobic, glycolytic, and phosphagen systems for alpine ski racers who perform SL and GS. Giant slalom specialists might benefit from emphasizing the improvement of the aerobic system, without neglecting other systems.

Purpose The purpose of this study was to examine differences in perceived exertion (RPE) and physiological responses for climbers of different abilities completing an identical route low and high above the ground. Materials and methods Forty-two male (N = 18) and female (N = 24) sport climbers divided into three groups, lower-grade (N = 14), intermediate (N = 14), and advanced climbers (N = 14), completed two visits to a climbing gym, separated by 7 days. In a random order, the climbers completed a close-to-the-ground ascent (treadwall) and climb to height (climbing gym). Immediately after the test, climbers provided their RPE (6-20). Indirect calorimetry was used to assess physiological response during the ascent and recovery. Results The mean (±standard deviation) RPE was higher for lower-grade climbers when ascending the route on the wall (RPE = 12 ± 1) when compared to the treadwall route (RPE = 11 ± 1, P = 0.040; d = 0.41). For all ability groups, the physiological response was higher on the climbing gym wall as opposed to the treadwall: ventilation (P = 0.003, η p 2 = 0.199), heart rate (HR) (P = 0.005, η p 2 = 0.189), energy cost (EC) (P = 0.000, η p 2 = 0.501). The RPE demonstrated a moderate relationship with physiological variables (R 2 = 0.14 to R 2 = 0.45). Conclusion Climbing to height induced a greater metabolic stress than climbing at a low height (treadwall) and led to higher RPE for lower-grade climbers. In this study, RPE appeared to be a good proxy measure of the physiological demands for advanced climbers but not for intermediate and lower-grade climbers. Therefore, using RPE in climbing with less experienced athletes may perhaps overestimate actual exercise intensity and should be interpreted carefully.

Background The pathophysiology of heart failure with preserved ejection fraction (HFpEF) is complex and multifactorial. Chronotropic incompetence (ChI) has emerged as a crucial pathophysiological mechanism. Beta‐blockers, drugs with negative chronotropic effects, are commonly used in HFpEF, although current evidence does not support its routine use in these patients. Hypothesis We postulate beta‐blockers may have deleterious effects in HFpEF and ChI. This work aims to evaluate the short‐term effect of beta‐blockers withdrawal on functional capacity assessed by the maximal oxygen uptake (peakVO2) in patients with HFpEF and ChI. Methods This is a prospective, crossover, randomized (1:1) and multicenter study. After randomization, the clinical and cardiac rhythm will be continuously registered for 30 days. PeakVO2 is assessed by cardiopulmonary exercise testing (CPET) at 15 and 30 days in both groups. Secondary endpoints include quality of life, cognitive, and safety assessment. Patients with stable HFpEF, functional class New York Heart Association (NYHA) II‐III, chronic treatment with beta‐blockers, and ChI will be enrolled. A sample size estimation [alfa: 0.05, power: 90%, a 20% loss rate, and delta change of mean peakVO2: +1.2 mL/kg/min (SD ± 2.0)] of 52 patients is necessary to test our hypothesis. Results Patients started enrolling in October 2018. As January 14th, 2020, 28 patients have been enrolled. It is projected to enroll the last patient at the end of July 2020. Conclusions Optimizing therapy that improves functional capacity remains an unmeet priority in HFpEF. Deprescribing beta‐blockers in patients with HFpEF and ChI seems a plausible intervention to improve functional capacity. This trial is an attempt towards precision medicine in this complex syndrome. Trial registration ClinicalTrials.gov: NCT03871803.

Purpose Reduction of noise of breath-by-breath gas-exchange data is crucial to improve measurements. A recently described algorithm ("independent breath"), that neglects the contiguity in time of breaths, was tested. Methods Oxygen, carbon dioxide fractions, and ventilatory flow were recorded continuously over 26 min in 20 healthy volunteers at rest, during unloaded and moderate intensity cycling and subsequent recovery; oxygen uptake ([Formula: see text]) was calculated with the "independent breath" algorithm (IND) and, for comparison, with three other "classical" algorithms. Average [Formula: see text] and standard deviations were calculated for steady-state conditions; non-linear regression was run throughout the [Formula: see text] data of the transient phases (ON and OFF), using a mono-exponential function. Results Comparisons of the different algorithms showed that they yielded similar average [Formula: see text] at steady state (p = NS). The standard deviations were significantly lower for IND (post hoc contrasts, p 2 uptake values while reducing the overall noise of about 30%, which might result in the halving of the required number of repeated trials needed to assess the kinetic parameters of the ON transient.

Lomax, M, Mayger, B, Saynor, ZL, Vine, C, and Massey, HC. Practical considerations for assessing pulmonary gas exchange and ventilation during flume swimming using the MetaSwim metabolic cart. J Strength Cond Res 33(7): 1941–1953, 2019—The MetaSwim (MS) metabolic cart can assess pulmonary gas exchange and ventilation in aquatic environments. The aims of this study were: (a) to determine the agreement between minute ventilation (VE), pulmonary oxygen uptake (Vo 2), and carbon dioxide output (Vco 2) using the MS and Douglas bag (DB) methods during flume swimming; and (b) to assess the repeatability of these and other MS-derived parameters. Sixteen trained swimmers completed a combined incremental and supramaximal verification cardiopulmonary swimming test to determine maximal Vo 2, 2 progressive intensity swimming tests during which MS and DB measurements were made (agreement protocol), and 3–4 constant-velocity submaximal swimming tests during which only the MS was used (repeatability protocol). Agreement was determined using limits of agreement (LoA), bias, random error, and 95% confidence intervals with systematic bias assessed using paired samples t-tests. Within-trial and between-trial repeatability were determined using the coefficient of variation (CV) and the repeatability coefficient (CR). Where data were heteroscedastic, LoA and CR were log-transformed, antilogged, and displayed as ratios. MetaSwim underestimated peak Vo 2 and Vco 2 (≤0.39 L·min−1) and VE (9.08 L·min−1), whereas submaximal values varied between 2 and 5% for CV and ±1.09–1.22 for ratio CR. The test-retest CV during constant-velocity swimming for VE, tidal volume, breathing frequency, Vo 2, Vco 2, and end-tidal pressures of O2 and CO2 was <9% (ratio CR of ±1.09–1.34). Thus, the MS and DB cannot be used interchangeably. Whether the MS is suitable for evaluating ventilatory and pulmonary responses in swimming will depend on the size of effect required.

Objective: To explore the validity of the Actigraph and the influence of the placement of the sensor when estimating the active energy expenditure in four common daily activities (transfers, manual task, walking in overground and walking up and down stairs) in stroke survivors. Design: Cross-sectional study. Setting: Department of Physical Medicine and Rehabilitation. Subjects: A total of 46 subjects affected with stroke sequelae were wearing the Actigraph on three different locations—ankle, hip and wrist on the non-affected side—and performed four tasks: transfers, manual task, walking on flat ground and walking up and down stairs. Main measures: The values of active energy expenditure estimated by the Actigraph were compared to those measured by a portable breathing gas exchange analyzer Metamax3B. The accuracy and agreement between Actigraph and Metamax values were analyzed with mean bias, root mean square error, correlation coefficient and Bland–Altman plots for each task and each sensor location. Results: The mean bias between the Metamax and Actigraph placed on wrist, hip and ankle were, respectively, MD = 1.16 kcal (%MD = 3%), MD =−20.44 kcal (%MD =−58%) and MD = 17.64 kcal (%MD = 50%). The agreement with the Metamax was poor in general regardless of the sensor location and type of task ( r = 0.12–0.58). Conclusion: This study found large differences and a poor agreement between the active energy expenditure as measured by the Actigraph and the Metamax according to the location of the sensor and the type of task performed by the subject.

Objectives To provide a scientific rationale for lower water temperature and wetsuit rules for elite and subelite triathletes. Methods 11 lean, competitive triathletes completed a 20 min flume swim, technical transition including bike control and psychomotor testing and a cycle across five different wetsuit and water temperature conditions: with wetsuit: 10°C, 12°C and 14°C; without wetsuit (skins): 14°C and 16°C. Deep body (rectal) temperature (Tre), psychomotor performance and the ability to complete a technical bike course after the swim were measured, as well as swimming and cycling performance. Results In skins conditions, only 4 out of 11 athletes could complete the condition in 14°C water, with two becoming hypothermic (Tre<35°C) after a 20 min swim. All 11 athletes completed the condition in 16°C. Tre fell further following 14°C (mean 1.12°C) than 16°C (mean 0.59°C) skins swim (p=0.01). In wetsuit conditions, cold shock prevented most athletes (4 out of 7) from completing the swim in 10°C. In 12°C and 14°C almost all athletes completed the condition (17 out of 18). There was no difference in temperature or performance variables between conditions following wetsuit swims at 12°C and 14°C. Conclusion The minimum recommended water temperature for racing is 12°C in wetsuits and 16°C without wetsuits. International Triathlon Union rules for racing were changed accordingly (January 2017).

A moderate hypoxic stimulus is considered a promising therapeutic modality for several pathological states including obesity. There is scientific evidence suggesting that when hypoxia and physical activity are combined, they could provide benefits for the obese population. The aim of the present study was to investigate if exposure to hypoxia combined with two different protocols of high-intensity interval exercise in overweight/obese women was more effective compared with exercise in normoxia. Study participants included 82 overweight/obese women, who started a 12 week program of 36 sessions, and were randomly divided into four groups: (1) aerobic interval training in hypoxia (AitH; FiO2 = 17.2%; n = 13), (2) aerobic interval training in normoxia (AitN; n = 15), (3) sprint interval training in hypoxia (SitH; n = 15), and (4) sprint interval training in normoxia (SitN; n = 18). Body mass, body mass index, percentage of total fat mass, muscle mass, basal metabolic rate, fat, and carbohydrate oxidation, and fat and carbohydrate energy were assessed. Outcomes were measured at baseline (T1), after 18 training sessions (T2), 7 days after the last session (T3), and 4 weeks after the last session (T4). The fat mass in the SitH group was significantly reduced compared with the SitN group from T1 to T3 (p p p p p = 0.022) compared with the AitN group from T1 to T4. All training groups showed a reduction in the percentage of fat mass, with a statistically significant reduction in the hypoxia groups (p p < 0.05), especially at T4. While fat oxidation tended to increase and oxidation of carbohydrates tended to decrease in both hypoxia groups, the tendency was reversed in the normoxia groups. Thus, high-intensity interval training under normobaric intermittent hypoxia for 12 weeks in overweight/obese women seems to be promising for reducing body fat content with a concomitant increase in muscle mass.

It is common practice in India to consume the dairy drink buttermilk as a way of mitigating occupational heat strain. This paper explores the thermoregulatory and hydration benefits of drinking buttermilk but also the impacts of work in a hot environment on the gut microbiota, renal and cognitive function. Twelve healthy participants were subjected to a 3-h period of medium load physical intermittent work in a climatic chamber (34°C, 60% RH). The subjects were given water, buttermilk (700 ml) or no rehydration at random. Mean body temperatures when no rehydration was given were significantly higher (p≤0.001). When subjects drank water or buttermilk they had a lower sweat rate than with no rehydration (p≤0.05) and the perception of feeling hot, uncomfortable, thirsty and physically exerted was significantly reduced (p≤0.05). A hormonal stress response at the end of the exposure was seen when not drinking (p≤0.05). No differences in cognitive abilities and gut microbiota were found. The exposure lowered the renal blood flow suggesting an acute impact of short term heat exposure. It was also found that buttermilk has a protective effect on this impact. Our results demonstrated that keeping hydrated by water/buttermilk consumption mitigates heat strain in well-nourished subjects.

Background The purpose of this study was to analyze the extent to which minimal dose strength training would elicit improvements in running performance for female recreational runners. Methods Forty-one female recreational runners were randomly assigned to one of three groups (endurance running [E] N.=14; combined endurance running and strength training program once [ES30] N.=14 and twice a week [ES60] N.=13, respectively). During the 10-week training program, the E group completed 3 hours of continuous endurance running per week; ES30 completed 2 ½ hours of continuous endurance running and 1 x 30 min of strength training per week, while ES60 group completed 2 hours of continuous endurance running and 2x30 min of strength training per week. Body composition, standing long jump, running economy and maximal endurance performance characteristics were assessed using ANOVA with repeated measures. Results Both concurrent training groups significantly improved their maximum treadmill test performance, ES30 from 168.5±43.2 to 191.3±43.8 s, ES60 from 203.1±47.8 to 249.3±49.7 s. No significant differences were detected between and within groups for body composition, power output (standing long jump), exercise economy and V̇O2max. Conclusions The findings suggest strength training in volume 30 min or 1 hour per week was sufficient to increase maximal running performance, however it did not lead to improvement in running economy or aerobic capacity.

Background Sodium‐glucose linked transporter 2 inhibition recently emerged as a promising therapy for reducing the risk of heart failure (HF) in patients with type 2 diabetes mellitus (T2DM). However, there is a lack of data endorsing its role in symptomatic HF patients. We sought to evaluate the short‐term effects of empagliflozin on maximal exercise capacity in these patients. Hypothesis We postulate tretament with empagliflozin may improve functional capacity in patients with T2DM and established HF. Methods Nineteen T2DM patients with symptomatic HF were prospectively included and underwent cardiopulmonary exercise testing before and 30 days after initiation of empagliflozin therapy. A mixed‐effects model for repeated measures was used. Results Median patient age was 72 years (interquartile range, 60–79 years); 42.1% were in New York Heart Association class III. Baseline mean (± SD) peak oxygen consumption (peak VO2) was 10.9 ± 4.0 mL/min/kg. Peak VO2 increased significantly at 30 days (∆: +1.21 [0.66 to 1.76] mL/min/kg; P < 0.001). A significant improvement in ventilatory efficiency during exercise, 6‐minute walking distance, and quality of life, and a reduction in antigen carbohydrate 125, were also found. Estimated glomerular filtration rate and natriuretic peptides did not significantly change. Conclusions In this pilot study, empagliflozin was associated with 1‐month improvement in exercise capacity in T2DM patients with symptomatic HF. This beneficial effect was also found for other surrogates of severity.

INTRODUCTION The obesity pandemic requires development of methods that could be used on a large scale, such as the cardiopulmonary exercise test (CPET). Gene expression may explain CPET results on the molecular level. OBJECTIVES The aim of this study was to compare gene expression in obesity, depending on CPET results. PATIENTS AND METHODS The study group consisted of 9 obese patients and 7 controls. The treatment encompassed diet, rehabilitation, and behavioral therapy. Diet was based on the body composition analyzed by bioelectrical impedance, resting metabolic rate, and subjective patient preferences. The rehabilitation depended on the CPET results: maximal oxygen uptake and fatty acid metabolism. Behavioral intervention focused on the diagnosis of health problems leading to obesity, lifestyle modification, training in self‑assessment, and development of healthy habits. The intensive treatment lasted for 12 weeks and consisted of consultations with a physician, dietitian, and medical rehabilitation specialist. RNA was isolated from the whole blood. A total of 47 323 transcripts were analyzed, of which 32 379 entities were confirmed to have high quality of RNA. RESULTS We observed differences in gene expression related to the CPET results indicating abnormalities in fat oxidation and maximal oxygen uptake. The genes with major differences in expression were: CLEC12A, HLA‑DRB1, HLA‑DRB4, HLA‑A29.1, IFIT1, and LOC100133662. CONCLUSIONS The differences in gene expression may account for the outcomes of treatment related to inflammation caused by obesity, which affects the muscles, fat tissue, and fatty acid metabolism.

New Findings What is the central question of this study? Do the pulmonary vascular responses to hypoxia change during progressive exposure to high altitude and can alterations in these responses be related to changes in concentrations of circulating biomarkers that affect the pulmonary circulation? What is the main finding and its importance? In our field study with healthy volunteers, we demonstrate changes in pulmonary artery pressure suggestive of remodelling in the pulmonary circulation, but find no changes in the acute responsiveness of the pulmonary circulation to changes in oxygenation during 2 weeks of exposure to progressive hypoxia. Pulmonary artery pressure changes were associated with changes in erythropoietin, 8‐isoprostane, nitrite and guanosine 3′,5′‐cyclic monophosphate. We sought to determine whether changes in pulmonary artery pressure responses to hypoxia suggestive of vascular remodelling occur during progressive exposure to high altitude and whether such alterations are related to changes in concentrations of circulating biomarkers with known or suspected actions on the pulmonary vasculature during ascent. We measured tricuspid valve transvalvular pressure gradients (TVPG) in healthy volunteers breathing air at sea level (London, UK) and in hypoxic conditions simulating the inspired O2 partial pressures at two locations in Nepal, Namche Bazaar (NB, elevation 3500 m) and Everest Base Camp (EBC, elevation 5300 m). During a subsequent 13 day trek, TVPG was measured at NB and EBC while volunteers breathed air and hyperoxic or hypoxic mixtures simulating the inspired O2 partial pressures at the other locations. For each location, we determined the slope of the relationship between TVPG and arterial oxygen saturation () to estimate the pulmonary vascular response to hypoxia. Mean TVPG breathing air was higher at any at EBC than at sea level or NB, but there was no change in the slope of the relationship between and TVPG between locations. Nitric oxide availability remained unchanged despite increases in oxidative stress (elevated 8‐isoprostane). Erythropoietin, pro‐atrial natriuretic peptide and interleukin‐18 levels progressively increased on ascent. Associations with TVPG were observed only with erythropoietin, 8‐isoprostane, nitrite and guanosine 3′,5′‐cyclic monophosphate. Although the increased TVPG for any given at EBC suggests that pulmonary vascular remodelling might occur during 2 weeks of progressive hypoxia, the lack of change in the slope of the relationship between TVPG and indicates that the acute pulmonary vascular responsiveness to changes in oxygenation does not vary within this time frame.

Background The neuropsychological consequences of exposure to environmental hypobaric hypoxia (EHH) remain unclear. We thus investigated them in a large group of healthy volunteers who trekked to Mount Everest base camp (5,300 m). Methods A neuropsychological (NP) test battery assessing memory, language, attention, and executive function was administered to 198 participants (age 44.5±13.7 years; 60% male). These were studied at baseline (sea level), 3,500 m (Namche Bazaar), 5,300 m (Everest Base Camp) and on return to 1,300 m (Kathmandu) (attrition rate 23.7%). A comparable control group (n = 25; age 44.5±14.1 years; 60% male) for comparison with trekkers was tested at/or near sea level over an equivalent timeframe so as to account for learning effects associated with repeat testing. The Reliable Change Index (RCI) was used to calculate changes in cognition and neuropsychological function during and after exposure to EHH relative to controls. Results Overall, attention, verbal ability and executive function declined in those exposed to EHH when the performance of the control group was taken into account (RCI .05 to -.95) with decline persisting at descent. Memory and psychomotor function showed decline at highest ascent only (RCI -.08 to -.56). However, there was inter-individual variability in response: whilst NP performance declined in most, this improved in some trekkers. Cognitive decline was greater amongst older people (r = .42; p < .0001), but was otherwise not consistently associated with socio-demographic, mood, or physiological variables. Conclusions After correcting for learning effects, attention, verbal abilities and executive functioning declined with exposure to EHH. There was considerable individual variability in the response of brain function to sustained hypoxia with some participants not showing any effects of hypoxia. This might have implications for those facing sustained hypoxia as a result of any disease.

Background The evidence on the associations of cardiorespiratory fitness, body adiposity and sports participation with arterial stiffness in children and adolescents with chronic diseases or physical disabilities is limited. Methods Altogether 140 children and adolescents with chronic diseases or physical disabilities participated in this cross-sectional study. Cardiorespiratory fitness was assessed using maximal exercise test with respiratory gas analyses either using shuttle run, shuttle ride, or cycle ergometer test. Cardiorespiratory fitness was defined as peak oxygen uptake by body weight or fat-free mass. Body adiposity was assessed using waist circumference, body mass index standard deviation score and body fat percentage. Sports participation was assessed by a questionnaire. Aortic pulse wave velocity and augmentation index were assessed by a non-invasive oscillometric tonometry device. Results Peak oxygen uptake/body weight (standardised regression coefficient β -0.222, 95% confidence interval (CI) -0.386 to -0.059, P = 0.002) and peak oxygen uptake/fat-free mass (β -0.173, 95% CI -0.329 to -0.017, P = 0.030) were inversely and waist circumference directly (β 0.245, 95% CI 0.093 to 0.414, P = 0.002) associated with aortic pulse wave velocity. However, the associations of the measures of cardiorespiratory fitness with aortic pulse wave velocity were attenuated after further adjustment for waist circumference. A higher waist circumference (β -0.215, 95% CI -0.381 to -0.049, P = 0.012) and a higher body mass index standard deviation score (β 0.218, 95% CI -0.382 to -0.054, P = 0.010) were related to lower augmentation index. Conclusions Poor cardiorespiratory fitness and higher waist circumference were associated with increased arterial stiffness in children and adolescents with chronic diseases and physical disabilities. The association between cardiorespiratory fitness and arterial stiffness was partly explained by waist circumference.

Patients with coronary heart disease or acute myocardial infarction after cardiac catheterization with stenting referred for phase II cardiac rehabilitation (CR) were grouped according to their preference. Cardio-pulmonary exercise testing (CPET) was used to determine oxygen uptake ((Equation is included in full-text article.)) at peak exercise and anaerobic threshold (AT). The control patients received counseling only while the experiment group received 36 sessions of CR in 3 to 6 months. Exercise physiology parameters and serum myokines (myostatin, insulin-like growth factor-1 (IGF-1), and interleukin-6 (IL-6) were measured pre- and postrehabilitation.There were 29 patients in the experiment group and 10 in the control group, with no significant differences in baseline parameters. The experiment group had prominent progress in aerobic capacity and body composition after CR, but their serum myokine concentrations did not change significantly. Serum myostatin is positively correlated to peak (Equation is included in full-text article.)pre- and post-training, and pretraining AT (Equation is included in full-text article.), after adjusting for age, sex, and body composition. Serum IGF-1 is positively correlated with grip strength before training.Serum myostatin level is positively correlated to aerobic capacity, and IGF-1 level is positively correlated to grip strength in cardiac patients receiving CR.

Purpose To derive and validate a single metric of activity tracking that associates with lower risk of cardiovascular disease mortality. Methods We derived an algorithm, Personalized Activity Intelligence (PAI), using the HUNT Fitness Study (n = 4631), and validated it in the general HUNT population (n = 39,298) aged 20-74 years. The PAI was divided into three sex-specific groups (≤50, 51-99, and ≥100), and the inactive group (0 PAI) was used as the referent. Hazard ratios for all-cause and cardiovascular disease mortality were estimated using Cox proportional hazard regressions. Results After >1 million person-years of observations during a mean follow-up time of 26.2 (SD 5.9) years, there were 10,062 deaths, including 3867 deaths (2207 men and 1660 women) from cardiovascular disease. Men and women with a PAI level ≥100 had 17% (95% confidence interval [CI], 7%-27%) and 23% (95% CI, 4%-38%) reduced risk of cardiovascular disease mortality, respectively, compared with the inactive groups. Obtaining ≥100 PAI was associated with significantly lower risk for cardiovascular disease mortality in all prespecified age groups, and in participants with known cardiovascular disease risk factors (all P-trends <.01). Participants who did not obtain ≥100 PAI had increased risk of dying regardless of meeting the physical activity recommendations. Conclusion PAI may have a huge potential to motivate people to become and stay physically active, as it is an easily understandable and scientifically proven metric that could inform potential users of how much physical activity is needed to reduce the risk of premature cardiovascular disease death.

Scientists such as physiologists, engineers, and nutritionists have often sought to estimate human metabolic strain during daily activities and physical pursuits. The measurement of human metabolism can involve direct calorimetry as well as indirect calorimetry using both closed-circuit respirometry and open-circuit methods that can include diluted flow chambers and laboratory-based gas analysis systems. For field studies, methods involving questionnaires, pedometry, accelerometery, heart rate telemetry, and doubly labelled water exist, yet portable metabolic gas analysis remains the gold standard for most field studies on energy expenditure. This review focuses on research-based portable systems designed to estimate metabolic rate typically under steady-state conditions by critically examining each significant historical innovation. Key developments include Zuntz's 1906 innovative system, then a significant improvement to this purely mechanical system by the widely adopted Kofranyi-Michaelis device in the 1940s. Later, a series of technical improvements: in electronics lead to Wolf's Integrating Motor Pneumotachograph in the 1950s; in polarographic O2 cells in 1970-1980's allowed on-line oxygen uptake measures; in CO2 cells in 1990s allowed on-line respiratory exchange ratio determination; and in advanced sensors/computing power at the turn of the century led to the first truly breath-by-breath portable systems. Very recent significant updates to the popular Cosmed and Cortex systems and the potential commercial release of the NASA-developed 'PUMA' system show that technological developments in this niche area are still incrementally advancing.

Background In the subacute stroke phase, the monitoring of ambulatory activity and activities of daily life with wearable sensors may have relevant clinical applications. Do current commercially available wearable activity trackers allow us to objectively assess the energy expenditure of these activities? The objective of the present study was to compare the energy expenditure evaluated by indirect calorimetry during the course of a scenario consisting of everyday activities while estimating the energy expenditure using several commercialised wearable sensors in post-stroke patients (less than six months since stroke). Method Twenty-four patients (age 68.2 ± 13.9; post-stroke delay 34 ± 25 days) voluntarily participated in this study. Each patient underwent a scenario of various everyday tasks (transfer, walking, etc.). During the implementation, patients wore 14 wearable sensors (Armband, Actigraph GT3X, Actical, pedometer) to obtain an estimate of the energy expenditure. The actual energy expenditure was concurrently determined by indirect calorimetry. Results Except for the Armband worn on the non-plegic side, the results of our study show a significant difference between the energy expenditure values estimated by the various sensors and the actual energy expenditure when the scenario is considered as a whole. Conclusion The present results suggest that, for a series of everyday tasks, the wearable sensors underestimate the actual energy expenditure values in post-stroke patients in the subacute phase and are therefore not accurate. Several factors are likely to confound the results: types of activity, prediction equations, the position of the sensor and the hemiplegia side.

Background The purpose of this review is to describe the evolution of portable open-circuit spirometry systems, and discuss their validity, reliability, and principles of operation. Methods Eleven devices were selected for review: the Oxylog, Aerosport KB1-C, Cosmed K2, Cosmed K4RQ, Cosmed K4b2, MetaMax I, MetaMax II, Metamax3B/VmaxST, Medgraphics VO2000, Oxycon Mobile I and Oxycon Mobile II. The validity (compared to the Douglas bag method [DBM]) and reliability of each device for measuring VO2 was summarized. Results Mean differences in resting measurements of VO2 were within ±0.05 L/min for all devices except one (difference of 0.17 L/min). When compared to the DBM, VO2 differences for all devices ranged from 0.01 L/min to 0.29 L/min during submaximal intensity exercise and from 0.01 L/min to 0.36 L/min during vigorous/maximal intensity. During submaximal and maximal intensities, ICC ranged from 0.66-0.99 and CV ranged from 2.0-14.2%. Of these devices, four used breath-by-breath technology and six used micro-proportional sampling technology. Validity and reliability of devices did not seem to differ between methods of gas collection. Conclusions Of the three commercially available devices in 2015, all were found to be reliable. Two of the three systems (Cosmed K4b2 and Oxycon Mobile II) provided valid estimates of VO2 (mean values within ±0.10 L/min of DBM) during rest, and submaximal and maximal intensities, while the MetaMax3B slightly overestimated VO2, particularly at maximal exercise.

Coronary heart disease (CHD) is a major cause of morbidity and mortality in developed countries. Metabolic syndrome (MetS) is associated with increased risk of CHD. Cardiac rehabilitation is considered an effective intervention and a Class I indication in patients with CHD. This study was designed to evaluate the effects of home‐based, integrated cardiac rehabilitation (HBICR) of patients with CHD in modifiable risk‐factor control and exercise capacity. Sixty‐four patients with CHD were investigated and randomized into intervention and control groups. The intervention group received a HBICR containing medication use, exercise program, smoking‐cessation counseling, and education regarding risk factors, nutrition, and the necessity of continuing the program, whereas the control group received traditional care. Baseline and follow‐up assessments at 3 months and 12 months, including body composition, metabolic syndrome risk score, and biochemical tests were performed in all patients. Additionally, cardiopulmonary function tests were also performed at baseline and 3‐month follow‐up assessments. There was a significant between‐group, within‐group, and interaction effect found in the MetS Z scores. Significant within‐group effects were also observed in modified Adult Treatment Panel III score, waist circumference, high‐density lipoprotein, and low‐density lipoprotein. However, several cardiopulmonary parameters did not differ significantly at 3‐month follow‐up between the two groups, including peak V̇O2, peak heart rate, peak respiratory exchange ratio, anaerobic threshold V̇O2, heart‐rate reserve, and heart‐rate recovery after 1 min and after 2 min. Our results showed that HBICR exhibited significant positive effects on modifiable risk‐factor control in CHD patients.

Background Classic teaching suggests that diminished availability of oxygen leads to increased tissue oxygen extraction yet evidence to support this notion in the context of hypoxaemia, as opposed to anaemia or cardiac failure, is limited. Methods At 75 m above sea level, and after 7-8 days of acclimatization to 4559 m, systemic oxygen extraction [C(a-v)O2] was calculated in five participants at rest and at peak exercise. Absolute [C(a-v)O2] was calculated by subtracting central venous oxygen content (CcvO2) from arterial oxygen content [Formula: see text] in blood sampled from central venous and peripheral arterial catheters, respectively. Oxygen uptake [Formula: see text] was determined from expired gas analysis during exercise. Results Ascent to altitude resulted in significant hypoxaemia; median (range) [Formula: see text] 87.1 (82.5-90.7)% and [Formula: see text] 6.6 (5.7-6.8) kPa. While absolute C(a-v)O2 was reduced at maximum exercise at 4559 m [83.9 (67.5-120.9) ml litre(-1) vs 99.6 (88.0-151.3) ml litre(-1) at 75 m, P=0.043], there was no change in oxygen extraction ratio (OER) [C(a-v)O2/CaO2] between the two altitudes [0.52 (0.48-0.71) at 4559 m and 0.53 (0.49-0.73) at 75 m, P=0.500]. Comparison of C(a-v)O2 at peak [Formula: see text] at 4559 m and the equivalent [Formula: see text] at sea level for each participant also revealed no significant difference [83.9 (67.5-120.9) ml litre(1) vs 81.2 (73.0-120.7) ml litre(-1), respectively, P=0.225]. Conclusion In acclimatized individuals at 4559 m, there was a decline in maximum absolute C(a-v)O2 during exercise but no alteration in OER calculated using central venous oxygen measurements. This suggests that oxygen extraction may have become limited after exposure to 7-8 days of hypoxaemia.

Heat stress caused by protective clothing limits work time. Performance improvement of a microclimate cooling method that enhances evaporative and to a minor extent convective heat loss was tested. Ten male volunteers in protective overalls completed a work-rest schedule (130 min; treadmill: 3 × 30 min, 3 km/h, 5% incline) with or without an additional air-diffusing garment (climatic chamber: 25°C, 50% RH, 0.2 m/s wind). Heat loss was supported by ventilating the garment with dry air (600 l/min, ≪5% RH, 25°C). Ventilation leads (M ± SD, n = 10, ventilated vs. non-ventilated) to substantial strain reduction (max. HR: 123 ± 12 b/min vs. 149 ± 24 b/min) by thermal relief (max. core temperature: 37.8 ± 0.3°C vs. 38.4 ± 0.4°C, max. mean skin temperature: 34.7 ± 0.8°C vs. 37.1 ± 0.3°C) and offers essential extensions in performance and work time under thermal insulation. Practitioner summary Heat stress caused by protective clothing limits work time. Performance can be improved by a microclimate cooling method that supports evaporative and to a minor extent convective heat loss. Sweat evaporation is the most effective thermoregulatory mechanism for heat dissipation and can be enhanced by insufflating dry air into clothing.

The purpose of this study was to investigate the relationship between dynamic hyperinflation and dyspnea and to clarify the characteristics of dyspnea during the 6-minute walk test (6MWT) in chronic obstructive pulmonary disease patients. Twenty-three subjects with stable moderate chronic obstructive pulmonary disease (age 73.8±5.8 years, all male) took part in this study. During the 6MWT, ventilatory and gas exchange parameters were measured using a portable respiratory gas analysis system. Dyspnea and oxygen saturation were recorded at the end of every 2 minute period during the test. There was a significant decrease in inspiratory capacity during the 6MWT. This suggested that dynamic hyperinflation had occurred. Dyspnea showed a significant linear increase, and there was a significant negative correlation with inspiratory capacity. It was suggested that one of the reasons that dyspnea developed during the 6MWT was the dynamic hyperinflation. Even though the tidal volume increased little after 2 minutes, dyspnea increased linearly to the end of the 6MWT. These results suggest that the mechanisms generating dyspnea during the 6MWT were the sense of respiratory effort at an early stage and then the mismatch between central motor command output and respiratory system movement.

Aim. The aim of this study was to examine the relationship between submaximal and maximal physiological responses to rock climbing for climbers of differing abilities.Methods. Twenty-six male climbers performed a submaximal climbing test on a known circuit at 90° (vertical) and 105° (15° overhanging) inclination and speed 25 movements·min−1. A maximal test was undertaken on a similar circuit at the same speed with inclination increasing by 10° for each successive 3 min stage.Results. Mean oxygen consumption and heart rate (HR) increased with wall inclination and climbers reached a mean (±SD) peakV˙O2of 40.3 ± 3.5 mL·kg−1·min−1during the maximal test. Self-reported climbing ability was negatively correlated withV˙O2and HR during the submaximal test at 90° (V˙O2,r=−0.82; HR, andr=−0.66) and at 105° (V˙O2,r=−0.84; HR, andr=−0.78) suggesting an increased exercise economy for climbers with a higher ability level.Conclusion. Findings from this study indicate that there is a relationship between wall inclination and the physiological demand of a climb. However, the increased technical ability and fitness of higher level climbers appears to an extent to offset the increased demand through improved exercise economy which in turn leads to an increased time to exhaustion and an improvement in performance.

The aim of the study was to assess the effects of climbing ability and slope inclination on vertical loading both in terms the forces involved and physiological responses. Five novice and six intermediate female climbers completed a climbing route at three slope inclinations (85°, 90°, and 98°). The vertical loading during the climb was assessed by force-time integral using a Novel Pedar-X insole and physiological responses via oxygen uptake and heart rate. The novice climbers had a significantly lower (p < 0.05) vertical loading on foot holds and higher oxygen uptake and heart rate compared to intermediate climbers. A significant negative correlation was identified between the force-time integral and oxygen uptake (R = -0.72), and with heart rate (R = -0.64), respectively. The time-force integral decreased across the ascents with increasing slope inclination (p < 0.001). The results indicate that more advanced ability climbers make greater use of foot holds, with associated lowering in physiological response (oxygen uptake and heart rate) across all slope inclinations.

Metabolic Rate Prediction in Young and Old Men by Heart Rate, Ambient Temperature, Weight and Body Fat Percentage: Satoru UENO,et al. National Institute of Occupational Safety and Health— Objectives An estimation of metabolic rate (MR) is needed to determine wet‐bulb globe temperature (WBGT) reference values in order to reduce heat strain in physical workers. The aim of this study was to develop MR prediction equation for younger and older men in hot working environments. Methods We measured the MR and heart rate (HR) of both younger and older men at ambient temperatures (Ta) of 25, 30 and 35°C while they cycled on a bicycle ergometer at a workload of 30, 45 and 60% of maximal oxygen uptake . (V ). Seven younger male university students agedO2max 22.9 ± 0.7 (mean ± SD) years and seven older male workers aged 61.7 ± 2.2 (mean ± SD) years participated in this study. MR, HR and rectal temperature (Tre) were measured during the study. HR, ambient temperature (Ta), body weight (BW) and body fat percentage (BF) served as predictors of MR using multivariate analysis. To increase the MR prediction accuracy, the following three alternative predictors of HR were used: HRres, calculated as 100 × [(HR − resting HR) / (maximal HR − resting HR)]; HRnet, calculated as (HR − resting HR); and HRi, calculated as (HR / resting HR). Results The R2value indicated that the models with HR or res HR were more accurate than those with HRor HR. net i Tahad a significantly positive correlation with MR in older men. BW had a significantly positive correlation with MR in both younger and older men, and BF had a significantly negative correlation with MR in both younger and older men. Conclusions HR or HR res net enabled more accurate MR prediction than HR. BW and BF would increase the accuracy of MR prediction.

Background High-intensity interval training (HIT) as exercise therapy is gradually implemented in cardiac rehabilitation as the cardiovascular benefits from exercise is intensity dependent. However, in previous studies, HIT has been performed with strict supervision. The aim of the study was to assess the feasibility and effectiveness of different modes of HIT in cardiac rehabilitation. Design a randomized clinical study. Methods Ninety participants with coronary artery disease (80 men/10 women, mean age 57 ± 8 years) were randomly assigned to one of three exercise modes: group exercise (GE), treadmill exercise (TE), or home-based exercise (HE). HIT was performed twice a week for 12 weeks with an exercise intensity of 85-95% of peak heart rate. The primary outcome measure was change in peak oxygen uptake (peak VO2). Results Eighty-three participants (92%) completed the intervention without any severe adverse events. Peak VO2 increased from 34.7 ± 7.3 to 39.0 ± 8.0 ml/kg/min, 32.7 ± 6.5 to 36.0 ± 6.2 ml/kg/min, and 34.4 ± 4.8 to 37.2 ± 5.2 ml/kg/min in TE, GE, and HE, respectively. Mean group difference for TE vs. HE was 1.6 ml/kg/min (95% confidence interval, CI, 0.7 to 3.1, p = 0.02), TE vs. GE 1.1 ml/kg/min (95% CI-0.5 to 2.5, p = 0.27), and GE vs. HE 0.6 ml/kg/min (95% CI -1.0 to 2.1, p = 1). However, on-treatment analysis showed no significant difference between groups. Conclusion HIT was efficiently performed in three settings of cardiac rehabilitation, with respect to target exercise intensity, exercise attendance, and increase in peak VO2. Exercise mode was not essential for exercise capacity.

Five protective garments (light summer clothing L, high visibility clothing HV, military clothing MIL, climber coverall CLM and firefighting clothing FIRE) were assessed on eight unacclimated male subjects at two environments: moderate warm environment with high humidity (MWH, 20.0°C, 86% relative humidity) and warm environment with moderate humidity (WMH, 30.0°C, 47% relative humidity). The thermophysiological responses and subjective sensations were reported. The PHS model (ISO7933) was used for predicting thermophysiological responses for each testing scenario. It was found that there were significant differences between clothing FIRE and other clothing on thermal sensation (p<0.05). Significant differences were found on skin humidity sensation between FIRE and L, HV or MIL (p<0.001). The RPE value in FIRE is significantly different with L and HV (p<0.05). In MWH, the post-exercise mean skin temperatures increased by 0.59 and 1.29°C in MIL and CLM. In contrast, mean skin temperatures in L, HV, MIL, CLM and FIRE in WMH increased by 1.7, 2.1, 2.1, 2.8 and 3.3°C, respectively. The PHS model presented good performance on predicted mean skin temperatures in MIL and CLM at the two studied environments. However, the skin temperature prediction with light clothing in WMH was weak. For thick protective clothing, the prediction on rectal temperature was protective. It is thus concluded that the results generated by the PHS model for high insulating clothing and measurements performed in high humidity environments should be explained with caution.

This study compared the effects of whole body vibration (WBV) and a field‐based re‐warm‐up during half‐time (HT) on subsequent physical performance measures during a simulated soccer game. Ten semi‐professional male soccer players performed 90‐min fixed‐intensity soccer simulations (SAFT90), using a multi‐directional course. During the HT period players either remained seated (CON), or performed intermittent agility exercise (IAE), or WBV. At regular intervals during SAFT90, vastus lateralis temperature (Tm) was recorded, and players also performed maximal counter‐movement jumps (CMJ), 10‐m sprints, and knee flexion and extension contractions. At the start of the second half, sprint and CMJ performance and eccentric hamstring peak torque were significantly reduced compared with the end of the first half in CON (P≤0.05). There was no significant change in these parameters over the HT period in the WBV and IAE interventions (P>0.05). The decrease in Tm over the HT period was significantly greater for CON and WBV compared with IAE (P≤0.01). A passive HT interval reduced sprint, jump and dynamic strength performance. Alternatively, IAE and WBV at HT attenuated these performance decrements, with limited performance differences between interventions.

This study investigated the performance of the portable Cortex Metamax 3B (MM3B) automated gas analysis system during both simulated and human exercise using adolescents. Repeated measures using a Gas Exchange System Validator (GESV) across a range of simulated metabolic rates, showed the MM3B to be adequately reliable (both percentage errors, and percentage technical error of measurements <2%) for measuring expired ventilation (V (E)), oxygen consumption (VO(2)), and carbon dioxide production (VCO(2)). Over a 3 h period, the MM3B was shown to be acceptably stable in measuring gas fractions, as well as V (E), VO(2), and VCO(2) generated by the GESV, especially at moderate and high metabolic rates (drifts <2% and of minor physiological significance). Using eight healthy adolescents during rest, moderate, and vigorous cycle ergometry, the validity of the MM3B was tested against the primary criterion Douglas bag method (DBM) and a secondary criterion machine known to be accurate, the Jaeger Oxycon Pro system. No significant errors in V (E) were noted, yet the MM3B significantly overestimated both VO(2) and VCO(2) by approximately 10-17% at moderate and vigorous exercise as compared to the DBM and at all exercise levels compared to the Oxycon Pro. No significant differences were seen in any metabolic variable between the two criterion systems (DBM and Oxycon Pro). It is concluded the MM3B produces acceptably stable and reliable results, but is not adequately valid during moderate and vigorous exercise without some further correction of VO(2) and VCO(2).

Context Tournament season can provoke overreaching syndrome in professional tennis players, which may lead to deteriorated performance. Thus, appropriate recovery methods are crucial for athletes in order to sustain high-level performance and avoid injuries. We hypothesized that whole-body cryostimulation could be applied to support the recovery process. Objective To assess the effects of 5 days of whole-body cryostimulation combined with moderate-intensity training on immunologic, hormonal, and hematologic responses; resting metabolic rate; and tennis performance in a posttournament season. Design Controlled laboratory study. Setting National Olympic Sport Centre. Patients or Other Participants Twelve high-ranking professional tennis players. Intervention(s) Participants followed a moderate-intensity training program. A subgroup was treated with the 5-day whole-body cryostimulation (−120°C) applied twice a day. The control subgroup participated in the training only. Main Outcome Measure(s) Pretreatment and posttreatment blood samples were collected and analyzed for tumor necrosis factor α, interleukin 6, testosterone, cortisol, and creatine kinase. Resting metabolic rate and performance of a tennis drill were also assessed. Results Proinflammatory cytokine (tumor necrosis factor α) decreased and pleiotropic cytokine (interleukin 6) and cortisol increased in the group exposed to cryostimulation. In the same group, greater stroke effectiveness during the tennis drill and faster recovery were observed. Neither the training program nor cryostimulation affected resting metabolic rate. Conclusions Professional tennis players experienced an intensified inflammatory response after the completed tournament season, which may lead to overreaching. Applying whole-body cryostimulation in conjunction with moderate-intensity training was more effective for the recovery process than the training itself. The 5-day exposure to cryostimulation twice a day ameliorated the cytokine profile, resulting in a decrease in tumor necrosis factor α and an increase in interleukin 6.

Aims Exercise is recommended as prevention, management, and control of all stages of hypertension. There are still controversies about the optimal training dose, frequency, and intensity. We aimed to study the effect of aerobic interval training on blood pressure and myocardial function in hypertensive patients. Methods and results A total of 88 patients (52.0 ± 7.8 years, 39 women) with essential hypertension were randomized to aerobic interval training (AIT) (>90% of maximal heart rate, correlates to 85-90% of VO(2max)), isocaloric moderate intensity continuous training (MIT) (~70% of maximal heart rate, 60% of VO(2max)), or a control group. Exercise was performed on a treadmill, three times per week for 12 weeks. Ambulatory 24-hour blood pressure (ABP) was the primary endpoint. Secondary endpoints included maximal oxygen uptake (VO(2max)), mean heart rate/24 hour, flow mediated dilatation (FMD), total peripheral resistance (TPR), and myocardial systolic and diastolic function by echocardiography. Systolic ABP was reduced by 12 mmHg (p < 0.001) in AIT and 4.5 mmHg (p = 0.05) in MIT. Diastolic ABP was reduced by 8 mmHg (p < 0.001) in AIT and 3.5 mmHg (p = 0.02) in MIT. VO(2max) improved by 15% (p < 0.001) in AIT and 5% (p < 0.01) in MIT. Systolic myocardial function improved in both exercise groups, diastolic function in the AIT group only. TPR reduction and increased FMD were only observed in the AIT group. Conclusions This study indicates that the blood pressure reducing effect of exercise in essential hypertension is intensity dependent. Aerobic interval training is an effective method to lower blood pressure and improve other cardiovascular risk factors.

Objective: Exercise capacity strongly predicts survival and aerobic interval training (AIT) increases peak oxygen uptake effectively in cardiac patients. Usual care in Norway provides exercise training at the hospitals following myocardial infarction (MI), but the effect and actual intensity of these rehabilitation programmes are unknown. Design: Randomized controlled trial. Setting: Hospital cardiac rehabilitation. Subjects: One hundred and seven patients, recruited two to 12 weeks after MI, were randomized to usual care rehabilitation or treadmill AIT. Interventions: Usual care aerobic group exercise training or treadmill AIT as 4 × 4 minutes intervals at 85–95% of peak heart rate. Twice weekly exercise training for 12 weeks. Main measures: The primary outcome measure was peak oxygen uptake. Secondary outcome measures were endothelial function, blood markers of cardiovascular disease, quality of life, resting heart rate, and heart rate recovery. Results: Eighty-nine patients (74 men, 15 women, 57.4 ± 9.5 years) completed the programme. Peak oxygen uptake increased more ( P = 0.002) after AIT (from 31.6 ± 5.8 to 36.2 ± 8.6 mL·kg −1 ·min −1 , P < 0.001) than after usual care rehabilitation (from 32.2 ± 6.7 to 34.7 ± 7.9 mL·kg −1 ·min −1 , P < 0.001). The AIT group exercised with significantly higher intensity in the intervals compared to the highest intensity in the usual care group (87.3 ± 3.9% versus 78.7 ± 7.2% of peak heart rate, respectively, P < 0.001). Both programmes increased endothelial function, serum adiponectin, and quality of life, and reduced serum ferritin and resting heart rate. High-density lipoprotein cholesterol increased only after AIT. Conclusions: AIT increased peak oxygen uptake more than the usual care rehabilitation provided to MI patients by Norwegian hospitals.

Background Exercise training is an important part of cardiac rehabilitation to reduce morbidity and mortality. Low-intensity exercise training can start as soon as the myocardial infarction (MI) patient is stable. Our objective was to evaluate the effect of an early start of exercise training in MI patients. Design A randomized controlled trial. Methods Thirty-nine MI patients were randomized to either an early start of exercise training group (EG) or to a delayed start control group (CG). The EG participated in an outpatient low-intensity EG (phase 2a) two times a week for 4 weeks before entering ordinary exercise training of moderate-to-high intensity (phase 2b). CG entered phase 2b directly after 4 weeks of delay. Primary outcome measure was peak oxygen consumption (VO2peak), measured at baseline, after 4 weeks and after 16 weeks. Secondary outcome measure was health-related quality of life. Results VO2peak did not change from baseline to 4 weeks, either in EG [30.6+/-6.7 ml/kg/min vs. 30.7+/-6.2 ml/kg/min, not significant (NS)] or CG (29.8+/-6.1 ml/kg/min vs. 30.7+/-6.2 ml/kg/min, NS). After 16 weeks VO2peak increased in both groups to 33.1+/-7.1 ml/kg/min in EG (P<0.005) and 33.0 ml/kg/min+/-8.6 in CG (P<0.005), group differences NSH. Health-related quality of life increased in every domain but physical functioning for both groups (group differences NS). Conclusion An early start of exercise training did not increase VO2peak compared to 4 weeks of delay. For low-risk patients with high motivation for exercise training, home-based walking is an option as a moderate start of cardiac rehabilitation the first weeks after MI.

The aim of this study was to determine the validity and reliability of a 90-minute soccer performance test: Ball-sport Endurance and Sprint Test (BEAST90). Fifteen healthy male amateur soccer players participated and attended 5 testing sessions over a 10-day period to perform physiologic and soccer-specific assessments. This included familiarization sessions and 2 full trials of the BEAST90, separated by 7 days. The total 90-minute distance, mean percent peak heart rate (HRpeak), and estimated percent peak oxygen uptake of the BEAST90 were 8,097 ± 458 m, 85 ± 5% and 82 ± 14%, respectively. Measures obtained from trial 1 and trial 2 were not significantly different (p > 0.05). Reliability of measures over 90 minutes ranged from 0.9-25.5% (% typical error). The BEAST90 protocol replicated soccer match play in terms of time, movement patterns, physical demands (volume and intensity), distances, and mean and HRpeak values, as well as having an aerobic load similar to that observed during a soccer match. Reproducibility of key physical measures during the BEAST90 were mostly high, suggesting good reliability. The BEAST90 could be used in studies that wish to determine the effects of training or nutritional interventions on prolonged intermittent physical performance.

The six-minute walk test (6-MWT) is widely used to assess functional status in patients with chronic heart failure (CHF). The aims of the present study were: (1) to compare metabolic gas exchange during the 6-MWT in older patients with left ventricular systolic dysfunction (LVSD) and in breathless patients with no major structural heart disease (MSHD); (2) to determine the exercise intensity of the 6-MWT relative to peak oxygen uptake; (3) to establish the accuracy and reproducibility of the Metamax 3B ergospirometer during an incremental workload. Twenty four older patients with LVSD (19 male; age 76 +/- 5 years; BMI 27 +/- 4), and 18 patients with no MSHD (12 male; age 75 +/- 8 years; BMI 27 +/- 4) attended on consecutive days at the same time. Patients completed a 6-MWT with metabolic gas exchange measurements using the Metamax 3B portable ergospirometer, and an incremental cycle ergometry test using both the Metamax 3B and Oxycon Pro metabolic cart. Patients returned and performed a second 6-MWT and an incremental treadmill test, metabolic gas exchange was measured with the Metamax 3B. In patients with LVSD, the 6-MWT was performed at a higher fraction of maximal exercise capacity (p = 0.02). The 6-MWT was performed below the anaerobic threshold in patients with LVSD (83 %) and in patients with no MSHD (61 %). The Metamax 3B showed satisfactory to high accuracy at 10 W and 20 W in patients with LVSD (r = 0.77 - 0.97, p < 0.05), and no MSHD (r = 0.76 - 0.94, p < 0.05). Metabolic gas exchange variables measured during the 6-MWT showed satisfactory to high day-to-day reproducibility in patients with LVSD (ICC = 0.75 - 0.98), but a higher variability was evident in participants with no MSHD (ICC = 0.62 - 0.97). The Metamax 3B portable ergospirometer is an accurate and reproducible device during submaximal, fixed rate exercise in older patients with LVSD and no MSHD. In elderly patients with LVSD and no MSHD, the 6-MWT should not be considered a maximal test of exercise capacity but rather a test of submaximal exercise performance. Our study demonstrates that the 6-MWT takes place at a higher proportion of peak oxygen uptake in patients with LVSD compared to those with no MSHD, and may be one reason why fatigue is a more prominent symptom in these patients.

Purpose The present study compared the effects of aerobic endurance training at different intensities and with different methods matched for total work and frequency. Responses in maximal oxygen uptake (VO2max), stroke volume of the heart (SV), blood volume, lactate threshold (LT), and running economy (CR) were examined. Methods Forty healthy, nonsmoking, moderately trained male subjects were randomly assigned to one of four groups:1) long slow distance (70% maximal heart rate; HRmax); 2)lactate threshold (85% HRmax); 3) 15/15 interval running (15 s of running at 90-95% HRmax followed by 15 s of active resting at 70% HRmax); and 4) 4 x 4 min of interval running (4 min of running at 90-95% HRmax followed by 3 min of active resting at 70%HRmax). All four training protocols resulted in similar total oxygen consumption and were performed 3 d.wk for 8 wk. Results High-intensity aerobic interval training resulted in significantly increased VO2max compared with long slow distance and lactate-threshold training intensities (P<0.01). The percentage increases for the 15/15 and 4 x 4 min groups were 5.5 and 7.2%, respectively, reflecting increases in V O2max from 60.5 to 64.4 mL x kg(-1) x min(-1) and 55.5 to 60.4 mL x kg(-1) x min(-1). SV increased significantly by approximately 10% after interval training (P<0.05). Conclusions : High-aerobic intensity endurance interval training is significantly more effective than performing the same total work at either lactate threshold or at 70% HRmax, in improving VO2max. The changes in VO2max correspond with changes in SV, indicating a close link between the two.

Background:Improved oxygen uptake improves soccer performance as regards distance covered, involvements with the ball, and number of sprints. Large improvements in oxygen uptake have been shown using interval running. A similar physiological load arising from interval running could be obtained using the soccer ball in training. Objectives:The main aim was to study physiological adaptations to a 10 week high intensity aerobic interval training program performed by professional youth soccer players, using a soccer specific ball dribbling track. Methods:Eleven youth soccer players with a mean (SD) age of 16.9 (0.4) years performed high intensity aerobic interval training sessions twice per week for 10 weeks in addition to normal soccer training. The specific aerobic training consisted of four sets of 4 min work periods dribbling a soccer ball around a specially designed track at 90–95% of maximal heart frequency, with a 3 min recovery jog at 70% of maximal heart frequency between intervals. Results:Mean Vo2maximproved significantly from 63.4 (5.6) to 69.8 (6.6) ml kg−1min−1, or 183.3 (13.2) to 201.5 (16.2) ml kg−0.75min−1(p<0.001). Squat jump and counter movement jump height increased significantly from 37.7 (6.2) to 40.3 (6.1) cm and 52.0 (4.0) to 53.4 (4.2) cm, respectively (p<0.05). No significant changes in body mass, running economy, rate of force development, or 10 m sprint times occurred. Conclusion:Performing high intensity 4 min intervals dribbling a soccer ball around a specially designed track together with regular soccer training is effective for improving the Vo2maxof soccer players, with no negative interference effects on strength, jumping ability, and sprinting performance.

Objective To determine the physiologic response of the 6-minute walk test (6-mwt) in children with juvenile idiopathic arthritis (JIA). Methods Eighteen children with JIA (age 7-17 years; 6 boys, 12 girls) performed a 6-mwt and a maximal exercise test. Results The physiologic response of the 6-mwt was on average between 80% and 85% of the peak values of heart rate and oxygen uptake (VO2peak) during the maximal exercise test, except for the minute ventilation, which had a mean percentage of 68.5%. Backward regression analysis showed that height and distance walked were the best predictors of VO2peak during cycling (R2 = 0.883, P < 0.001). During the 6-mwt, the difference between the first and second minute was significant in every variable, except for heart rate. The range of walking distance of children with JIA was comparable with that of healthy elderly people. Conclusion The physiologic response of the 6-mwt is at a submaximal, intense level of exercise. The course of the responses during the 6-mwt was normal. The 6-mwt can be regarded as a good test for measuring functional exercise capacity.

Background Increased aerobic exercise capacity appears to reduce both all-cause mortality and cardiovascular disease mortality. Physical exercise to improve peak oxygen uptake (VO2peak) is thus strongly recommended, however evidence regarding the most efficient training intensity for patients with coronary artery disease (CAD) is still lacking. The purpose of this randomized study was therefore to assess the effects of high intensity aerobic interval exercise compared to moderate intensity exercise, representing the same total training load, for increasing VO2peak in stable CAD-patients. Methods Twenty-one stable CAD-patients were randomized to supervised treadmill walking at either high intensity (80-90% of VO2peak) or moderate intensity (50-60% of VO2peak) three times a week for 10 weeks. Results After training VO2peak increased by 17.9% (P=0.012) in the high intensity group and 7.9% (P=0.038) in the moderate intensity group. The training-induced adaptation was significantly higher in the high intensity group (P=0.011). Conclusions High intensity aerobic interval exercise is superior to moderate exercise for increasing VO2peak in stable CAD-patients. As VO2peak seems to reflect a continuum between health and cardiovascular disease and death, the present data may be useful in designing effective training programmes for improved health in the future.

Background:In professional soccer, a significant amount of training time is used to improve players' aerobic capacity. However, it is not known whether soccer specific training fulfils the criterion of effective endurance training to improve maximal oxygen uptake, namely an exercise intensity of 90–95% of maximal heart rate in periods of three to eight minutes. Objective:To determine whether ball dribbling and small group play are appropriate activities for interval training, and whether heart rate in soccer specific training is a valid measure of actual work intensity. Methods:Six well trained first division soccer players took part in the study. To test whether soccer specific training was effective interval training, players ran in a specially designed dribbling track, as well as participating in small group play (five a side). Laboratory tests were carried out to establish the relation between heart rate and oxygen uptake while running on a treadmill. Corresponding measurements were made on the soccer field using a portable system for measuring oxygen uptake. Results:Exercise intensity during small group play was 91.3% of maximal heart rate or 84.5% of maximal oxygen uptake. Corresponding values using a dribbling track were 93.5% and 91.7%. No higher heart rate was observed during soccer training. Conclusions:Soccer specific exercise using ball dribbling or small group play may be performed as aerobic interval training. Heart rate monitoring during soccer specific exercise is a valid indicator of actual exercise intensity.

Physical tests and selection criteria have historically been used by many military organizations. However, the standards associated with them have come under increasing scrutiny in recent years. This paper describes a series of experiments that were conducted to establish task-related occupational tests and standards (TBTs) for Royal Naval (RN) personnel. A total of 172 (106 male and 66 female) RN personnel volunteered for these experiments, which were designed to: identify the anthropometric requirements for operating various safety hatches and doors on board a RN Frigate (TBT1); quantify the metabolic demands of shipboard firefighting tasks and establish an aerobic fitness standard (TBT2); and identify a battery of tests to predict performance of shipboard casualty-carrying tasks (TBT3). Whilst all subjects completed the criterion tasks during TBT1, performance of the bulkhead door (BD) escape task was related to height (r = 0.50- 0.62, P < 0.05) and vertical reach (r = 0.42-0.54, P < 0.05), with shorter subjects struggling to perform the task. During TBT2, the mean metabolic demand of representative firefighting tasks was 38 ml/min/kg, which must be sustained for 20-30 min. Finally, a battery of tests incorporating measures of lean body mass, fat mass, standing broad jump, 20 m sprint, press-ups, sit-ups and grip strength produced a high correlation (r = 0.89, P < 0.01) with casualty-carrying task performance. From the results of these experiments, it is recommended that RN personnel perform the BD simulation task at the recruitment stage (TBT1), to prove that they possess the anthropometric characteristics commensurate with survival at sea. Secondly, personnel should be frequently screened to ascertain whether they have the maximal aerobic power (41 ml/min/kg) commensurate with shipboard firefighting for 20-30 min (TBT2). Finally, they should perform the battery of proposed tests and score at least 34 points, in order to establish whether they have the anaerobic and strength capacity commensurate with shipboard casualty-carrying tasks (TBT3).