Exercise under heat stress: thermoregulation, hydration, performance implications, and mitigation strategies.

A rise in body core temperature and loss of body water via sweating are natural consequences of prolonged exercise in the heat. This review provides a comprehensive and integrative overview of how the human body responds to exercise under heat stress and the countermeasures that can be adopted to enhance aerobic performance under such environmental conditions. The fundamental concepts and physiological processes associated with thermoregulation and fluid balance are initially described, followed by a summary of methods to determine thermal strain and hydration status. An outline is provided on how exercise-heat stress disrupts these homeostatic processes, leading to hyperthermia, hypohydration, sodium disturbances, and in some cases exertional heat illness. The impact of heat stress on human performance is also examined, including the underlying physiological mechanisms that mediate the impairment of exercise performance. Similarly, the influence of hydration status on performance in the heat and how systemic and peripheral hemodynamic adjustments contribute to fatigue development is elucidated. This review also discusses strategies to mitigate the effects of hyperthermia and hypohydration on exercise performance in the heat by examining the benefits of heat acclimation, cooling strategies, and hyperhydration. Finally, contemporary controversies are summarized and future research directions are provided.

Effects of hypoxic compound exercise to promote HIF-1α expression on cardiac pumping function, sleep activity behavior, and exercise capacity in Drosophila.

Alteration of HIF-1α expression levels under hypoxic conditions affects the sequence of its downstream target genes thereby producing different effects. In order to investigate whether the effect of hypoxic compound exercise (HE) on HIF-1α expression alters cardiac pumping function, myocardial structure, and exercise capacity, we developed a suitable model of hypoxic exercise using Drosophila, a model organism, and additionally investigated the effect of hypoxic compound exercise on nocturnal sleep and activity behavior. The results showed that hypoxic compound exercise at 6% oxygen concentration for five consecutive days, lasting 1 h per day, significantly improved the cardiac stress resistance of Drosophila. The hypoxic complex exercise promoted the whole-body HIF-1α expression in Drosophila, and improved the jumping ability, climbing ability, moving speed, and moving distance. The expression of HIF-1α in the heart was increased after hypoxic exercise, which made a closer arrangement of myofilaments, an increase in the diameter of cardiac tubules, and an increase in the pumping function of the heart. The hypoxic compound exercise improved the sleep quality of Drosophila by increasing its nocturnal sleep time, the number of deep sleeps, and decreasing its nocturnal awakenings and activities. Therefore, we conclude that hypoxic compound exercise promoted the expression of HIF-1α to enhance the exercise capacity and heart pumping function of Drosophila, and improved the quality of sleep.

Physiological Characterization of Preserved Ratio Impaired Spirometry in the CanCOLD Study: Implications for Exertional Dyspnea and Exercise Intolerance.

Rationale: It is increasingly recognized that adults with preserved ratio impaired spirometry (PRISm) are prone to increased morbidity. However, the underlying pathophysiological mechanisms are unknown. Objectives: Evaluate the mechanisms of increased dyspnea and reduced exercise capacity in PRISm. Methods: We completed a cross-sectional analysis of the CanCOLD (Canadian Cohort Obstructive Lung Disease) population-based study. We compared physiological responses in 59 participants meeting PRISm spirometric criteria (post-bronchodilator FEV1 < 80% predicted and FEV1/FVC ⩾ 0.7), 264 control participants, and 170 ever-smokers with chronic obstructive pulmonary disease (COPD), at rest and during cardiopulmonary exercise testing. Measurements and Main Results: Individuals with PRISm had lower total lung, vital, and inspiratory capacities than healthy controls (all P < 0.05) and minimal small airway, pulmonary gas exchange, and radiographic parenchymal lung abnormalities. Compared with healthy controls, individuals with PRISm had higher dyspnea/[Formula: see text]o2 ratio at peak exercise (4.0 ± 2.2 vs. 2.9 ± 1.9 Borg units/L/min; P < 0.001) and lower [Formula: see text]o2peak (74 ± 22% predicted vs. 96 ± 25% predicted; P < 0.001). At standardized submaximal work rates, individuals with PRISm had greater Vt/inspiratory capacity (Vt%IC; P < 0.001), reflecting inspiratory mechanical constraint. In contrast to participants with PRISm, those with COPD had characteristic small airways dysfunction, dynamic hyperinflation, and pulmonary gas exchange abnormalities. Despite these physiological differences among the three groups, the relationship between increasing dyspnea and Vt%IC during cardiopulmonary exercise testing was similar. Resting IC significantly correlated with [Formula: see text]o2peak (r = 0.65; P < 0.001) in the entire sample, even after adjusting for airflow limitation, gas trapping, and diffusing capacity. Conclusions: In individuals with PRISm, lower exercise capacity and higher exertional dyspnea than healthy controls were mainly explained by lower resting lung volumes and earlier onset of dynamic inspiratory mechanical constraints at relatively low work rates. Clinical trial registered with www.clinicaltrials.gov (NCT00920348).

Prolyl isomerase Pin1 in skeletal muscles contributes to systemic energy metabolism and exercise capacity through regulating SERCA activity.

The skeletal muscle is a pivotal organ involved in the regulation of both energy metabolism and exercise capacity. There is no doubt that exercise contributes to a healthy life through the consumption of excessive energy or the release of myokines. Skeletal muscles exhibit insulin sensitivity and can rapidly uptake blood glucose. In addition, they can undergo non-shivering thermogenesis through actions of both the sarcoplasmic/endoplasmic reticulum Ca2+-ATPase (SERCA) and small peptide, sarcolipin, resulting in systemic energy metabolism. Accordingly, the maintenance of skeletal muscles is important for both metabolism and exercise. Prolyl isomerase Pin1 is an enzyme that converts the cis-trans form of proline residues and controls substrate function. We have previously reported that Pin1 plays important roles in insulin release, thermogenesis, and lipolysis. However, the roles of Pin1 in skeletal muscles remains unknown. To clarify this issue, we generated skeletal muscle-specific Pin1 knockout mice. Pin1 deficiency had no effects on muscle weights, morphology and ratio of fiber types. However, they showed exacerbated obesity or insulin resistance when fed with a high-fat diet. They also showed a lower ability to exercise than wild type mice did. We also found that Pin1 interacted with SERCA and elevated its activity, resulting in the upregulation of oxygen consumption. Overall, our study reveals that Pin1 in skeletal muscles contributes to both systemic energy metabolism and exercise capacity.

The Child Opportunity Index 2.0 and Disparities in Pediatric Cardiorespiratory Fitness.

OBJECTIVE: To evaluate the effect of neighborhood-level characteristics on cardiorespiratory fitness (CRF) via peak oxygen consumption (VO2peak) for healthy pediatric patients. STUDY DESIGN: The institutional cardiopulmonary exercise testing (CPET) database was analyzed retrospectively. All patients aged ≤ 18 years without a diagnosis of cardiac disease and with a maximal effort CPET were included. Patients were divided into three self-identified racial categories: White, Black, and Latinx. The Child Opportunity Index (COI) 2.0 was used to analyze social determinants of health. CRF was evaluated based on COI quintiles and race. Assessment of the effect of COI on racial disparities in CRF was performed using ANCOVA. RESULTS: A total of 1753 CPETs met inclusion criteria. The mean VO2peak was 42.1 ± 9.8 mL/kg/min. The VO2peak increased from 39.1 ± 9.6 mL/kg/min for patients in the very low opportunity cohort to 43.9 ± 9.4 mL/kg/min for patients in the very high opportunity cohort. White patients had higher percent predicted VO2peak compared with both Black and Latinx patients (P < .01 for both comparisons). The racial differences in CRF were no longer significant when adjusting for COI. CONCLUSION: In a large pediatric cohort, COI was associated with CRF. Racial disparities in CRF are reduced when accounting for modifiable risk factors.

Endovascular Ablation of the Right Greater Splanchnic Nerve in Heart Failure With Preserved Ejection Fraction: Rationale, Design and Lead-in Phase Results of the REBALANCE-HF Trial.

OBJECTIVE: Splanchnic vasoconstriction augments transfer of blood volume from the abdomen into the thorax, which may increase filling pressures and hemodynamic congestion in patients with noncompliant hearts. Therapeutic interruption of splanchnic nerve activity holds promise to reduce hemodynamic congestion in patients with heart failure with preserved ejection fraction (HFpEF). Here we describe (1) the rationale and design of the first sham-controlled, randomized clinical trial of splanchnic nerve ablation for HFpEF and (2) the 12-month results of the lead-in (open-label) trial's participants. METHODS: REBALANCE-HF is a prospective, multicenter, randomized, double-blinded, sham-controlled clinical trial of endovascular, transcatheter, right-sided greater splanchnic nerve ablation for volume management (SAVM) in patients with HFpEF. The primary objectives are to evaluate the safety and efficacy of SAVM and identify responder characteristics to inform future studies. The trial consists of an open-label lead-in phase followed by the randomized, sham-controlled phase. The primary efficacy endpoint is the reduction in pulmonary capillary wedge pressure (PCWP) at 1-month follow-up compared to baseline during passive leg raise and 20W exercise. Secondary and exploratory endpoints include health status (Kansas City Cardiomyopathy Questionnaire), 6-minute walk test distance, New York Heart Association class, and NTproBNP levels at 3, 6 and 12 months. The primary safety endpoint is device- or procedure-related serious adverse events at the 1-month follow-up. RESULTS: The lead-in phase of the study, which enrolled 26 patients with HFpEF who underwent SAVM, demonstrated favorable safety outcomes and reduction in exercise PCWP at 1 month post-procedure and improvements in all secondary endpoints at 6 and 12 months of follow-up. The randomized phase of the trial (n = 44 SAVM; n = 46 sham) has completed enrollment, and follow-up is ongoing. CONCLUSION: REBALANCE-HF is the first sham-controlled randomized clinical trial of greater splanchnic nerve ablation in HFpEF. Initial 12-month open-label results are promising, and the results of the randomized portion of the trial will inform the design of a future pivotal clinical trial. SAVM may offer a promising therapeutic option for patients with HFpEF. TRIAL REGISTRATION: NCT04592445.

Pulmonary rehabilitation improves exercise capacity, health-related quality of life, and cardiopulmonary function in patients with non-small cell lung cancer.

BACKGROUND: Lung cancer significantly impairs exercise capacity and health-related quality of life (HRQL). Pulmonary rehabilitation (PR) has demonstrated positive effects on exercise capacity and HRQL in lung cancer patients. However, its impact on cardiopulmonary function needs further exploration. The aim of this study was to explore the effects of PR on cardiopulmonary function, exercise capacity and HRQL in patients with lung cancer. METHODS: Patients with lung cancer were enrolled in a 12-week PR program. Each participant underwent a thorough evaluation, which included spirometry, cardiopulmonary exercise testing, respiratory muscle strength test, and evaluation of HRQL using the Chronic Obstructive Pulmonary Disease Assessment Test (CAT). RESULTS: Fifty-six patients completed the PR program. Following PR, exercise capacity significantly improved, as evidenced by increased peak oxygen uptake and work rate (both p < 0.05). Exertional symptoms were notably reduced, including leg soreness and dyspnea at peak exercise, accompanied by a decrease in the CAT score (all p < 0.05). Furthermore, improvements in cardiopulmonary function were observed, encompassing respiratory muscle strength, ventilatory equivalent, tidal volume, stroke volume index, and cardiac index at peak exercise (all p < 0.05). CONCLUSIONS: PR demonstrated notable enhancements in cardiopulmonary function, exertional symptoms, exercise capacity, and HRQL in patients with lung cancer.

Comprehensive Cardiac Rehabilitation Following Acute Myocardial Infarction Improves Clinical Outcomes Regardless of Exercise Capacity.

BACKGROUND: Reduced exercise capacity is a prognostic indicator of adverse outcomes in patients with acute myocardial infarction (AMI). However, few studies have evaluated the effectiveness of comprehensive cardiac rehabilitation (CR) in this population. This study aimed to clarify the efficacy of comprehensive CR in patients with AMI and reduced exercise capacity.Methods and Results: This cohort study included 610 patients with AMI who underwent percutaneous coronary intervention. Major adverse cardiovascular events (MACE) were compared between patients who participated in comprehensive outpatient CR for 150 days (CR group; n=430) and those who did not (non-CR group; n=180). During the mean (±SD) follow-up period of 6.1±4.0 years, the CR group exhibited a lower incidence of MACE (log-rank P=0.002). Multivariable analysis revealed that Killip classification, diuretics at discharge, and participation in comprehensive CR were independently associated with MACE. The CR group was further divided into 2 groups, namely reduced exercise capacity (% predicted peak V̇O2<80%; n=241) and preserved exercise capacity (≥80%; n=147), based on the initial cardiopulmonary exercise test. Despite distinct exercise capacities, the incidence of MACE was comparable and physical parameters improved similarly after comprehensive CR in both groups. CONCLUSIONS: Comprehensive CR in patients with AMI effectively reduced the incidence of MACE regardless of initial exercise capacity. Cardiologists should actively encourage patients with low exercise capacity to participate in comprehensive CR.

Effect of body mass index on exercise capacity following pediatric heart transplantation.

BACKGROUND: Obesity and impaired exercise tolerance following heart transplantation increase the risk of post-transplant morbidity and mortality. The aim of this study was to evaluate the effect of body mass index on markers of exercise capacity in pediatric heart transplant recipients and compare this effect with a healthy pediatric cohort. METHODS: A retrospective analysis of cardiopulmonary exercise test data between 2004 and 2022 was performed. All patients exercised on a treadmill using the Bruce protocol. Inclusion criteria included patients aged 6-21 years, history of heart transplantation (transplant cohort) or no cardiac diagnosis (control cohort) at the time of testing, and a maximal effort test. Patients were further stratified within these two cohorts as underweight, normal, overweight, and obese based on body mass index groups. Two-way analyses of variance were performed with diagnosis and body mass index category as the independent variables. RESULTS: A total of 250 exercise tests following heart transplant and 1963 exercise tests of healthy patients were included. Heart transplant patients across all body mass index groups had higher resting heart rate and lower maximal heart rate, heart rate recovery at 1 min, exercise duration, and peak aerobic capacity (VO2peak). Heart transplant patients in the normal and overweight body mass index categories had higher VO2peak and exercise duration when compared to underweight and obese patients. CONCLUSION: Underweight status and obesity are strongly associated with lower VO2peak and exercise duration in heart transplant patients. Normal and overweight heart transplant patients had the best markers of exercise capacity.

Effectiveness of Exercise Interventions on Body Composition, Exercise Capacity, Fatigue, and Quality of Life in Patients with Liver Cirrhosis: A Meta-Analysis of Randomized Controlled Trials.

BACKGROUND: Diminished muscle protein synthesis in cirrhosis leads to reduced strength and mass, impacting daily activities and overall quality of life. AIMS: This study aimed to examine the effectiveness of exercise intervention in body composition, exercise capacity, fatigue, and quality of life in patients with liver cirrhosis. METHODS: A systematic search of medical databases, including PubMed, Embase, Cochrane, and CINAHL, was executed from their inception to November 2022. The inclusion criteria were randomized controlled trials comparing exercise interventions with a control group that did not receive exercise interventions. RESULTS: From the initially identified 2,565 articles, eight studies with a total of 220 patients were eligible for inclusion in this meta-analysis. According to the meta-analysis, exercise significantly improved the six-minute walk distance (6MWD) by 68.93 m (95% CI 14.29-123.57) compared to the control group. Furthermore, the subgroup analysis revealed that combing exercise with amino acid supplementation had a greater positive effect on the 6MWD (MD = 144.72, 95% CI 87.44-202.01). Exercise also significantly increased thigh circumference (MD = 1.26, 95% CI 0.12-2.39) and the thigh ultrasound average compression index (MD = 0.07, 95% CI 0.00-0.14). Moreover, exercise significantly decreased fatigue levels by 0.7 points in patients with liver cirrhosis (95% CI 0.38-1.03). However, no significant effects were observed on body mass index (BMI), fat mass, fat-free mass, and quality of life. CONCLUSIONS: Exercise can improve exercise capacity, thigh muscle thickness, and fatigue in patients with cirrhosis, but it does not have a significant impact on fat mass, BMI, or quality of life.

Impact of preterm birth on muscle mass and function: a systematic review and meta-analysis.

Individuals born preterm present lower exercise capacity. Along with the cardiopulmonary responses and activity level, muscle strength is a key determinant of exercise capacity. This systematic review aimed to summarize the current knowledge on the impact of preterm birth on skeletal muscle mass and function across the lifespan. The databases PubMed, MEDLINE, EBM, Embase, CINAHL Plus, Global Index Medicus, and Google Scholar were searched using keywords and MeSH terms related to skeletal muscle, preterm birth, and low birth weight. Two independent reviewers undertook study selection, data extraction, and quality appraisal using Covidence review management. Data were pooled to estimate the prematurity effect on muscle mass and function using the R software. From 4378 studies retrieved, 132 were full-text reviewed and 25 met the inclusion/exclusion criteria. Five studies presented a low risk of bias, and 5 had a higher risk of bias due to a lack of adjustment for confounding factors and presenting incomplete outcomes. Meta-analyses of pooled data from homogenous studies indicated a significant reduction in muscle thickness and jump test (muscle power) in individuals born preterm versus full-term with standardized mean difference and confidence interval of - 0.58 (0.27, 0.89) and - 0.45 (0.21, 0.69), respectively.    Conclusion: Overall, this systematic review summarizing the existing literature on the impact of preterm birth on skeletal muscle indicates emerging evidence that individuals born preterm, display alteration in the development of their skeletal muscle mass and function. This work also highlights a clear knowledge gap in understanding the effect of preterm birth on skeletal muscle development. What is Known: • Preterm birth, which occurs at a critical time of skeletal muscle development and maturation, impairs the development of different organs and tissues leading to a higher risk of comorbidities such as cardiovascular diseases. • Preterm birth is associated with reduced exercise capacity. What is New: • Individuals born preterm display alterations in muscle mass and function compared to individuals born at term from infancy to adulthood. • There is a need to develop preventive or curative interventions to improve skeletal muscle health in preterm-born individuals.

Cardiopulmonary function in paediatric post-COVID-19: a controlled clinical trial.

Recently, the importance of post-COVID-19 in children has been recognized in surveys and retrospective chart analysis. However, objective data in the form of cardiopulmonary exercise test as performed in adults suffering from this condition are still lacking. This study aimed to investigate the cardiopulmonary effects of post-COVID-19 on children and adolescents. In this cross-sectional study (the FASCINATE study), children fulfilling the criteria of post-COVID-19 and an age- and sex-matched control group underwent cardiopulmonary exercise testing on a treadmill and completed a questionnaire with regard to physical activity before, during and after the infection with SARS-CoV-2. We were able to recruit 20 children suffering from post-COVID-19 (mean age 12.8 ± 2.4 years, 60% females) and 28 control children (mean age 11.7 ± 3.5 years, 50% females). All participants completed a maximal treadmill test with a significantly lower V ˙ O 2 peak in the post-COVID-19 group (37.4 ± 8.8 ml/kg/min vs. 43.0 ± 6.7 ml/kg/min. p = 0.019). This significance did not persist when comparing the achieved percentage of predicted V ˙ O 2 peak . There were no significant differences for oxygen pulse, heart rate, minute ventilation or breathing frequency.   Conclusion: This is the first study to investigate post-COVID-19 in children using the cardiopulmonary exercise test. Although there was a significantly reduced V ˙ O 2 peak in the post-COVID-19 group, this was not true for the percent of predicted values. No pathological findings with respect to cardiac or pulmonary functions could be discerned. Deconditioning was the most plausible cause for the experienced symptoms.    Trial registration: clinicaltrials.gov, NCT054445531, Low-field Magnetic Resonance Imaging in Pediatric Post Covid-19-Full Text View-ClinicalTrials.gov. What is Known: • The persistence of symptoms after an infection with SARS-CoV 2, so-called post-COVID-19 exists also in children. • So far little research has been conducted to analyze this entity in the pediatric population. What is New: • This is the first study proving a significantly lower cardiopulmonary function in pediatric patients suffering from post-COVID-19 symptoms. • The cardiac and pulmonary function appear similar between children suffering from post-COVID-19 and those who don't, but the peripheral muscles seem affected.

Use of 6-minute walk distance to predict lung transplant-free survival in fibrosing non-IPF interstitial lung diseases.

BACKGROUND AND OBJECTIVE: The identification of progression in patients with fibrosing non-idiopathic pulmonary fibrosis (IPF) interstitial lung diseases (ILDs) represents an ongoing clinical challenge. Lung function decline alone may have significant limitations in the detection of clinically significant progression. We hypothesized that longitudinal changes of 6-min walk distance (6MWD) from baseline, simultaneously considered with measures of lung function, may independently predict survival and identifying clinically significant progression of disease. METHODS: Forced vital capacity (FVC), diffusing lung capacity (DLCO) and 6MWD were considered both at baseline and at 1 year in a discovery cohort (n = 105) and in a validation cohort (n = 138) from different centres. The primary endpoint was lung transplant (LTx)-free survival. RESULTS: Average follow-up was 3 years in both cohorts. Combined incidence of deaths and LTx was 29% and 21%, respectively. No collinearity and no strong correlations were observed among FVC, DLCO and 6MWD longitudinal changes. While age, gender and BMI were not significant, 6MWD decline ≥24 m predicted LTx-free-survival significantly and independently from FVC and DLCO declines, with high sensitivity and specificity, in both the discovery and the validation cohorts. Although FVC and DLCO declines remained significant predictors of LTx-free survival, 6MWD decline was more accurate than the proposed ATS/ERS/JRS/ALAT functional criteria. Results were confirmed after stratifying patients by baseline FVC. CONCLUSION: Longitudinal declines of 6MWD are associated with poor survival in fibrosing ILDs across a wide range of baseline severity, with high accuracy. 6MWD longitudinal decline is largely independent from lung function decline and may be integrated into the routine assessment of progression.

Effects of Combined Endurance and Resistance Eccentric Training on Muscle Function and Functional Performance in Patients With Chronic Obstructive Pulmonary Disease: Randomized Controlled Trial.

OBJECTIVE: To evaluate the adherence to treatment and efficacy of an eccentric-based training (ECC) program on peripheral muscle function and functional exercise capacity in patients with chronic obstructive pulmonary disease (COPD). DESIGN: Prospective, assessor-blinded, randomized controlled trial. SETTING: The cardiopulmonary rehabilitation unit of a tertiary subacute referral center. PARTICIPANTS: Thirty (N=30) stable inpatients (mean age 68±8 years; FEV1 44±18% of predicted) with COPD were included in the study. INTERVENTIONS: Inpatients were randomly assigned to 4 weeks of a combined endurance and resistance ECC (n=15) or conventional training (CON; n=15). MAIN OUTCOME MEASURES: Quadriceps peak torque (PT) was the primary outcome measure for muscle function. Rate of force development (RFD), muscle activation and quality (quadriceps PT/leg lean mass), 6-min walk distance (6MWD), 4-meter gait speed (4mGS), 10-meter gait speed, 5-repetition sit-to-stand (5STS), dyspnea rate, and mortality risk were the secondary outcomes. Evaluations were performed at baseline and repeated after 4 weeks and 3 months of follow-up. RESULTS: Quadriceps PT, RFD, and muscle quality improved by 17±23% (P<.001), 19±24%, and 16±20% (both P<.05) within the ECC group. Besides, a significant between-group difference for RFD (56±94 Nm/s, P=.038) was found after training. Both groups showed clinically relevant improvements in 6MWD, 4mGS, dyspnea rate, and mortality risk, with no significant differences between groups. CONCLUSION: Combined endurance and resistance ECC improved lower limbs muscle function compared with CON in inpatients with COPD. In contrast, ECC did not further improve functional performance, dyspnea, and mortality risk. ECC may be of particular benefit to effect on skeletal muscle function in patients with COPD.

The Effect of Computerized Wobble Board and Core Stabilization Exercises on Balance Performance and Exercise Capacity in Patients With Heart Failure: A Randomized Controlled Trial.

OBJECTIVE: To investigate the effects of computerized wobble board exercise training (CWBET) and core stabilization exercise training (CSET) on balance performance, and exercise capacity in patients with heart failure (HF). DESING: Single-blind randomized controlled prospective study. SETTING: Cardiology department of a local university hospital. PARTICIPANTS: Fifty-one patients with HF with reduced ejection fraction, whose clinical status and medication had been stable for the previous 3 months, were included (N=51). Nine patients could not complete the follow-up period due to personal reasons. No patient experienced any adverse events during exercise training. INTERVENTIONS: Patients were randomized to CWBET, CSET, and control group. CWBET and CSET groups participated in their own exercise programs, 3 days a week for 8 weeks. The control group received no exercise program. MAIN OUTCOME MEASURES: All patients were evaluated at baseline and after 8 weeks. Postural stability, static and functional balance, and exercise capacity were evaluated with the Sensamove Balance Test Pro with Miniboard, the one-leg stance test (OLS), the Berg Balance Scale (BBS), and the six-minute walk distance (6MWD), respectively. Core stabilization and health-related quality of life (HRQOL) were assessed with OCTOcore app, and Minnesota Living with Heart Failure Questionnaire, respectively. RESULTS: A mixed model repeated-measures ANOVA revealed significant group × time interaction effect for static postural stability performance (P<.001, ηp2=0.472), vertical (P<.001, ηp2=0.513), horizontal performance (P<.001, ηp2=0.467), OLS (P<.001, ηp2=0.474), BBS (P<.001, ηp2=0.440) scores, 6MWD (P<.001, ηp2=0.706), and HRQOL. Post hoc analysis revealed CWBET and CSET groups had similar improvements balance performance, exercise capacity, and HRQOL and both groups significantly improved compared with control group (P<.001). Core stabilization was significantly improved only in CSET group after 8 weeks. CONCLUSION: CWBET and CSET programs were equally effective and safe for improving balance performance and exercise capacity in patients with HF.

Effect of Pulmonary Rehabilitation on Exercise Capacity, Dyspnea, Fatigue, and Peripheral Muscle Strength in Patients With Post-COVID-19 Syndrome: A Systematic Review and Meta-analysis.

OBJECTIVE: To establish the effects of pulmonary rehabilitation (PR) in patients with persistent symptoms after COVID-19 infection. In addition, to compare the modalities of PR services (face-to-face and telerehabilitation) and the duration of PR in weeks (4-8 weeks and >8 weeks). DATA SOURCES: PubMed/MEDLINE, Embase (Elsevier), Central/Cochrane Library, SciELO Citation Index (Web of Science), and CINAHL. STUDY SELECTION: Studies determining the effects of PR in patients with post-COVID-19 syndrome were included and grouped according to PR delivery modality. DATA EXTRACTION: Data extraction and quality assessment were independently performed by 2 reviewers. The methodological quality was assessed using the Cochrane Risk of Bias Tool 1 (RoB-1). DATA SYNTHESIS: The literature search retrieved 1406 articles, of which 7 studies explored the effects of PR on patients with post-COVID-19 syndrome, with 188 patients randomized to PR. The mean age of participants was 50 years and 49% were women. Meta-analysis showed an increase in exercise capacity with PR compared with control (6-minute walking test: mean difference: 60.56 m, 95% confidence interval: 40.75-80.36), a reduction in fatigue (Fatigue Severity Scale: -0.90, -1.49 to -0.31) but no change in dyspnea (-0.57, -1.32 to 0.17) and muscle strength (3.03, -1.89 to 7.96). There were no differences between telerehabilitation and face-to-face PR regarding effects on peripheral muscle strength (P=.42), dyspnea (P=.83), and fatigue (P=.34). There were no differences between programs 4-8 weeks and >8 weeks regarding exercise capacity (P=.83), peripheral muscle strength (P=.42), and dyspnea (P=.76). CONCLUSIONS: PR improves exercise capacity and reduces fatigue in patients with post-COVID-19 syndrome. Duration of PR (4-8 weeks vs > 8 weeks) or PR modality (telerehabilitation vs face-to-face) did not affect outcomes but data were limited and based on subgroup analysis. Further evidence is required to determine the optimal delivery mode and duration of PR for post-COVID-19 syndrome.

Inhaled beta2 -agonist, formoterol, enhances intense exercise performance, and sprint ability in elite cyclists.

PURPOSE: Many athletes use long-acting beta2 -agonist formoterol in treatment of asthma. However, studies in non-athlete cohorts demonstrate that inhaled formoterol can enhance sprint performance calling into question whether its use in competitive sports should be restricted. We investigated whether formoterol at upper recommended inhaled doses (54 µg) would enhance sprint ability and intense exercise performance in elite cyclists. METHODS: Twenty-one male cyclists (V̇O2max : 70.4 ± 4.3 mL × min-1 × kg-1 , mean ± SD) completed two 6-s all-out sprints followed by 4-min all-out cycling after inhaling either 54 µg formoterol or placebo. We also assessed cyclists' leg muscle mass by dual-energy X-ray absorptiometry and muscle fiber type distribution of vastus lateralis biopsies. RESULTS: Peak and mean power output during the 6-s sprint was 32 W (95% CI, 19-44 W, p < 0.001) and 36 W (95% CI, 24-48 W, p < 0.001) higher with formoterol than placebo, corresponding to an enhancing effect of around 3%. Power output during 4-min all-out cycling was 9 W (95% CI, 2-16 W, p = 0.01) greater with formoterol than placebo, corresponding to an enhancing effect of 2.3%. Performance changes in response to formoterol were unrelated to cyclists' VO2max and leg lean mass, whereas muscle fiber Type I distribution correlated with change in sprinting peak power in response to formoterol (r2 = 0.314, p = 0.012). CONCLUSION: Our findings demonstrate that an inhaled one-off dose of 54 µg formoterol has a performance-enhancing potential on sprint ability and short intense performance in elite male cyclists, which is irrespective of training status but partly related to muscle fiber type distribution for sprint ability.

Effects of a telerehabilitation program and detraining on cardiorespiratory fitness in patients with post-COVID-19 sequelae: A randomized controlled trial.

BACKGROUND: This study aimed to evaluate the effects of a 15-week telerehabilitation program and a detraining period on cardiorespiratory fitness and mechanical efficiency in patients with post-COVID-19 sequelae. METHODS: 131 patients with post-COVID-19 sequelae were randomly assigned to one of two groups: patients who carried out the supervised telerehabilitation program (TRG, n = 66) and a control group (CG, n = 65). An incremental cardiopulmonary exercise testing (CPET) was performed on cycle ergometer to compare cardioventilatory responses between experimental groups. RESULTS: A significant increase in the CPET duration, peak power output, and mechanical efficiency was observed in TRG compared to CG after the telerehabilitation program (p ≤ 0.001). A significant increase in the CPET duration, peak power output, and mechanical efficiency was verified at 3 months compared to the pretest and after detraining in TRG (p < 0.001). A significant increase in peak oxygen uptake (V̇O2peak ) was identified after the intervention and in the detraining period compared to the pretest in both experimental groups (p < 0.001). A higher ventilatory efficiency was observed after the telerehabilitation program (p = 0.021) than in pretest only in TRG. CONCLUSIONS: A 15-week supervised home telerehabilitation program improved exercise capacity, power output, and mechanical efficiency in TRG compared to a CG. The telerehabilitation program was not more effective in improving V̇O2peak than the activities of the CG. However, ventilatory efficiency was improved only after the telerehabilitation program. The reported results after the detraining period highlight the need to maintain the rehabilitation program over time.

Impairments of functional exercise capacity, muscle strength, balance and kinesiophobia in patients with chronic kidney disease: a cross-sectional study.

BACKGROUND: Muscle weakness, balance, and functional capacity are affected in patients with chronic kidney disease (CKD) in dialysis. However, studies about kinesiophobia, peripheral and respiratory muscle strength, balance, exercise capacity, fatigue, and physical activity level in patients with CKD 3-4 are limited. The study aimed to compare the functional exercise capacity, peripheral and respiratory muscle strength, pulmonary function, balance, kinesiophobia, physical activity, fatigue, and dyspnea between patients with CKD 3-4 and controls. METHODS: This cross-sectional study included 43 patients and 45 controls. Functional exercise capacity [6-Minute Walking Test (6MWT)], peripheral and respiratory muscle strength, pulmonary function, dyspnea, fatigue, physical activity, balance [Berg Balance Scale (BBS)], and kinesiophobia were evaluated. RESULTS: Demographic characteristics were similar in patients [53(50-57) y, 26 M/17F] and controls [51(4.506-55) y, 33 M/12F] (p > 0.05). The 6MWT, respiratory and peripheral muscle strength, pulmonary function, physical activity, and BBS were significantly lower, and the level of dyspnea and kinesiophobia were higher in patients compared with controls (p < 0.05). CONCLUSIONS: Patients had impaired functional exercise capacity, upper and lower extremity muscle strength, respiratory muscle strength, pulmonary function, and balance, increased perception of dyspnea and kinesiophobia, and reduced physical activity level compared with controls. Patients should be directed to cardiopulmonary rehabilitation programs.

Effect of twice daily inhaled albuterol on cardiopulmonary exercise outcomes, dynamic hyperinflation, and symptoms in secondhand tobacco-exposed persons with preserved spirometry and air trapping: a randomized controlled trial.

BACKGROUND: In tobacco-exposed persons with preserved spirometry (active smoking or secondhand smoke [SHS] exposure), air trapping can identify a subset with worse symptoms and exercise capacity. The physiologic nature of air trapping in the absence of spirometric airflow obstruction remains unclear. The aim of this study was to examine the underlying pathophysiology of air trapping in the context of preserved spirometry and to determine the utility of bronchodilators in SHS tobacco-exposed persons with preserved spirometry and air trapping. METHODS: We performed a double-blinded placebo-controlled crossover randomized clinical trial in nonsmoking individuals at risk for COPD due to exposure to occupational SHS who had preserved spirometry and air trapping defined as either a residual volume-to-total lung capacity ratio (RV/TLC) > 0.35 or presence of expiratory flow limitation (EFL, overlap of tidal breathing on maximum expiratory flow-volume loop) on spirometry at rest or during cardiopulmonary exercise testing (CPET). Those with asthma or obesity were excluded. Participants underwent CPET at baseline and after 4-week trials of twice daily inhalation of 180 mcg of albuterol or placebo separated by a 2-week washout period. The primary outcome was peak oxygen consumption (VO2) on CPET. Data was analyzed by both intention-to-treat and per-protocol based on adherence to treatment prescribed. RESULTS: Overall, 42 participants completed the entire study (66 ± 8 years old, 91% female; forced expiratory volume in 1 s [FEV1] = 103 ± 16% predicted; FEV1 to forced vital capacity [FVC] ratio = 0.75 ± 0.05; RV/TLC = 0.39 ± 0.07; 85.7% with EFL). Adherence was high with 87% and 93% of prescribed doses taken in the treatment and placebo arms of the study, respectively (P = 0.349 for comparison between the two arms). There was no significant improvement in the primary or secondary outcomes by intention-to-treat or per-protocol analysis. In per-protocol subgroup analysis of those with RV/TLC > 0.35 and ≥ 90% adherence (n = 27), albuterol caused an improvement in peak VO2 (parameter estimate [95% confidence interval] = 0.108 [0.014, 0.202]; P = 0.037), tidal volume, minute ventilation, dynamic hyperinflation, and oxygen-pulse (all P < 0.05), but no change in symptoms or physical activity. CONCLUSIONS: Albuterol may improve exercise capacity in the subgroup of SHS tobacco-exposed persons with preserved spirometry and substantial air trapping. These findings suggest that air trapping in pre-COPD may be related to small airway disease that is not considered significant by spirometric indices of airflow obstruction.