Peak Oxygen Uptake Research Articles

Low serum brain-derived neurotrophic factor may predict poor response to cardiac rehabilitation in patients with cardiovascular disease.

It has been shown that serum brain-derived neurotrophic factor (BDNF) is associated with skeletal muscle energy metabolism and that BDNF is a predictor of mortality in heart failure patients. However, little is known about the relationship between BDNF and cardiac rehabilitation (CR). Therefore, this study retrospectively investigated the effects of baseline serum BDNF levels on the CR-induced exercise capacity improvement in patients with cardiovascular disease (CVD). We assigned 99 CVD patients (mean age 71±12 years, male = 60) to Low, Middle, and High groups based on the tertiles of baseline BDNF levels. Cardiopulmonary exercise testing was done using supervised bicycle ergometer twice before and after 3 weeks of CR. Analysis of covariance (ANCOVA) followed by post-hoc analysis using Tukey's HSD test was conducted to assess the multivariate associations between baseline BDNF levels categorized by BDNF tertiles (as independent variable) and %increases in AT and peak VO2 after 3-week CR (as dependent variables) after adjustment for age and gender (as covariates), as a main statistical analysis of the present study. The higher the baseline BDNF levels, the better nutritional status evaluated by the CONUT score (p<0.0001). Baseline anaerobic threshold (AT) and peak oxygen uptake (peak VO2) were similar among the three groups. ANCOVA followed by post-hoc analysis revealed that age- and gender-adjusted %increases in peak VO2 after 3-week CR were positively associated with baseline BDNF levels (p = 0.0239) and Low BDNF group showed significantly lower %increase in peak VO2 than High BDNF group (p = 0.0197). Significant association was not found between baseline BDNF and %increase in AT (p = 0.1379). Low baseline BDNF levels were associated with malnutrition in CVD patients. A positive association between baseline BDNF levels and CR-induced increases in peak VO2 was found. It was suggested that CVD patients with low baseline BDNF levels may be poor responders to CR.

Impact of midsole thickness on physiological responses during running in well-trained athletes

Introduction Modern running shoes have revolutionized long-distance performances by decreasing the amount of oxygen athletes need when running at a given speed, which is termed running economy. In 2022, World Athletics imposed an upper limit of 40 mm for midsole thickness, possibly to prevent shoes from having an overemphasized role in performance. This ceiling, however, seems arbitrary, and a better understanding of whether midsole thickness affects running economy is needed. This study therefore investigated if midsole thickness affects oxygen consumption both indoors and outdoors, as early findings from treadmill studies may not translate to overground running. Methods Following a familiarization trial including an incremental test, 16 well-trained male runners (weight 70 ± 6 kg, age 28 ± 5 years, peak oxygen uptake, V̇O2peak 64 ± 4 ml O2･kg-1･min-1, peak running speed 20.0 ± 0.8 km･h-1) completed two testing visits, once on a treadmill and once on a track, each consisting of twelve 5-min runs at submaximal speed (16 km･h-1) alternating three different footwear conditions: an entry-level running shoe (EL, 30 mm midsole thickness) and two carbon-plated modern running shoes with midsole thickness of 40 and 50 mm, respectively. The shoe order was randomized and balanced between each of the four replicates. Gas exchange and heart rate were continuously measured throughout the runs. Results Running with 40 mm shoes reduced V̇O2 compared with EL shoes by 2.4 ± 1.1% on the treadmill and 4.0 ± 1.2% when running overground (both p &lt; 0.001). Running with 50mm shoes also decreased V̇O2 compared with EL shoes both on the treadmill (-2.7 ± 1.6%, p &lt; 0.001) and overground (-4.6 ± 1.8%, p &lt; 0.001), but no differences were detected between the modern shoes (40 mm vs. 50 mm treadmill: +0.3 ± 1.3%, p = 0.586; overground: +0.6 ± 1.4%, p = 0.189). Similarly, heart rate was lower compared with the EL shoes in both the 40 mm shoes (treadmill -1.3 ± 0.6%; overground -2.0 ± 0.6%; both p &lt; 0.001) and 50 mm shoes (treadmill -1.6 ± 0.7%; overground -2.3 ± 0.6%, both p &lt; 0.001), but no differences were detected between the modern shoes (40 mm vs. 50 mm treadmill: +0.3% ± 0.6%, p = 0.106; overground: +0.4 ± 0.6%, p = 0.090). Interestingly when running overground V̇O2 decreased over time for the 50 mm shoes, reaching significance between replicates 1 and 4 (p = 0.017), which was not the case for the 40 mm shoes (p = 0.817). The V̇O2 ratio between the 50 mm and 40 mm shoes was 1.003 in replicate 1 and 0.987 in replicate 4 (p = 0.108). Discussion/Conclusion Our data suggests that a 50 mm midsole does not offer significant benefits compared with race-legal 40 mm midsole shoes when tested over short durations. The 50 mm shoes cause a noticeable decrease in V̇O2 over time when used outdoors, which may reflect a learning effect to this unfamiliar midsole thickness. Longer test sessions may be necessary to reveal the actual impact on running economy of shoes with over 40 mm midsoles.

Body plethysmography - additional information on exercise capacity in patients with congenital heart disease?

In each cardiopulmonary exercise test (CPET), resting spirometry is performed in advance. In patients with a congenital heart defect (CHD), lung volumes are often impaired. This study investigates correlations between lung volumes and CPET parameters and determines, whether body plethysmography provides substantial additional information for these patients. Data from 102 patients (23.8 ± 10.4years of age, 39 female) with various forms of CHD were examined from April 2018 to October 2022. All patients underwent spirometry (measuring forced vital capacity, FVC and forced expiratory volume in 1s, FEV1), body plethysmography (measuring total lung capacity, TLC) and an exhausting CPET. Data is presented as the median and interquartile range (z-scores) and correlated with Spearman's rho. Fifty-five% of all patients had normal results in lung function and 45% had normal peak oxygen uptake (≥ 80% predicted in peak VO2). Patients with impaired lung function were significantly more likely to have low exercise capacity (Fisher's exact test: p = 0.028). FVC z-values and %predicted peak VO2 (r = 0.365, p < 0.001) correlated significantly as well as FEV1_z and %predicted peak VO2 (r = 0.320, p = 0.001), and TLC z-values and %predicted peak VO2 (r = 0.249, p = 0.012). No correlation was found between FEV1/FVC z-values and %predicted peak VO2 (r = -0.043, p = 0.670). Spirometry and exercise capacity positively correlate, also in CHD patients. However, body plethysmography does not provide additional or improved prediction and is therefore only recommended in noteworthy results in spirometry to exclude further lung co-morbidities.

Cardiopulmonary Exercise Performance of Children Born Non-Extremely Preterm.

Data on exercise tolerance of children born non-extremely preterm are sparse. We aimed to explore the cardiopulmonary exercise testing (CPET) characteristics in this population. We studied 63 children (age 7-12 years) born at 290/7-366/7 weeks of gestation (34 were late preterm, 29 were preterm) and 63 age-matched, term-born controls. All performed spirometry and CPET (cycle ergometry). There were no differences in activity levels and spirometric parameters between the group of preterm-born children and controls. A peak oxygen uptake (VO2peak) of <80% was noted in 25.4% of the term-born and 49.2% of preterm-born children (p = 0.001). Term-born participants presented similar VO2peak to late-preterm children but higher than those born at <340/7 weeks of gestation (p = 0.002). Ventilatory limitation was noted in 4.8% of term and 7.9% of preterm participants, while only one preterm child presented cardiovascular limitation. Children born before 34 weeks of gestation had higher respiratory rates and smaller tidal volumes at maximum exercise, as well as lower oxygen uptake for the level of generated work. We conclude that school-age children born at 29-34 weeks of gestation may present decreased exercise performance attributed to an altered ventilatory response to exercise and impaired O2 utilization by their skeletal muscles rather than other cardiopulmonary limiting factors.

Sex Differences in Depressive Symptoms in 1308 Patients Post-Stroke at Entry to Cardiac Rehabilitation.

The objective of this study was to determine whether a sex difference exists in the prevalence of post-stroke depressive symptoms (PSDS) at entry to cardiac rehabilitation (CR) and to determine the correlates of PSDS in all patients, and in women and men separately. People post-stroke at entry to CR from database records (2006-2017) were included. Bivariate analyses identified PSDS correlates (≥16 on the Center for Epidemiologic Studies Depression Scale) in all patients and women and men separately. Patients (n = 1308, 28.9% women), mean age of 63.9 ± 12.9 yr, were 24.2 ± 9.9 mo post-stroke at CR entry. Among all patients, 30.0% had PSDS. A greater proportion of women than men had PSDS (38.6 vs 26.6%; P < .001). Correlates of PSDS in all patients were sex (women) (OR = 1.6: 95% CI, 1.14-2.12), being unemployed, ≤60 yr old, prescribed antidepressant medication, having lower cardiorespiratory fitness (peak oxygen uptake [V̇ o2peak ]), chronic obstructive pulmonary disease (COPD), higher body mass index (BMI), no transient ischemic attack, and longer time from stroke to CR entry (>12 mo). Correlates in women were being obese (BMI ≥ 30), 51-70 yr old, prescribed antidepressant medication, and not married. Correlates in men were being ≤60 yr old, unemployed, prescribed antidepressant medication, having lower V̇ o2peak , sleep apnea, COPD, and no hypertension. Women were disproportionately affected by PSDS at entry to CR in bivariate and multivariable analyses. Women and men had mostly unique correlates of PSDS, indicating tailored strategies to address PSDS are required. PSDS disproportionately affected patients with longer delay to CR entry, suggesting efforts should target timely referral to facilitate earlier and repeated assessments and management.

Effects of a randomized-controlled and online-supported physical activity intervention on exercise capacity, fatigue and health related quality of life in patients with post-COVID-19 syndrome

BackgroundThe Post-COVID-19 syndrome (PCS), which can occur after acute respiratory syndrome coronavirus 2 infection, leads to restrictions in everyday activity. Our study assessed the impact of an online-guided intervention which intended to facilitate physical activity on the mental and physical capability of PCS patients.MethodsWe randomized 62 patients with PCS (20 male/ 42 female; age: 46 ± 12 years; body mass index: 28.7 ± 6.7 kg/m2) with a score ≥ 22 in the fatigue assessment scale (FAS) to a 3-month exercise-focused intervention (IG n = 30) or control period (CG n = 32). We assessed changes in exercise capacity (bicycle exercise test with measurements of gas exchange), fatigue, markers of health-related quality of life (HrQoL) and mental health.ResultsThe FAS score decreased significantly in both study groups (IG: 35.1 ± 7.4 to 31.8 ± 8.5 points; CG: 35.6 ± 7.4 to 32.6 ± 7.5 points, both p < 0.01). Exercise capacity did not increase in the CG or IG (within-group changes for IG: peak oxygen uptake: 0.9 ± 2.6 ml/min/kg, p = 0.098; peak power output: 6.1 ± 17.8 W, p = 0.076) with no significant changes in HrQoL and work ability. Patients with a FAS score at baseline ≥ 35 (severe fatigue) showed no change in exercise capacity with the 3-month intervention whereas the sub-group of patients with FAS < 35 points (moderate fatigue) showed improvements, independent of the study group.ConclusionsOur 3-month intervention seems appropriate for patients with moderate fatigue, whereas those with more severe fatigue appear to be too restricted with respect to their mental or physical health status to perform exercise at a level which is sufficient to improve markers of physical performance.Trial registrationGerman Clinical Trials Register (registration trial number: DRKS00026245) on September 2 2021.

Performance-Determining Variables of a Simulated Sprint Cross-Country Skiing Competition.

To investigate performance-determining variables of an on-snow sprint cross-country skiing competition and the evolvement in their relationship with performance as the competition progresses from the individual time trial (TT) to the final. Sixteen national-level male junior skiers (mean [SD] age, 18.6 [0.8]y; peak oxygen uptake [VO2peak], 67.6 [5.5]mL·min-1·kg-1) performed a simulated sprint competition (1.3km) in the skating style, comprising a TT followed by 3 finals (quarterfinals, semifinals, and final) completed by all skiers. In addition, submaximal and incremental roller-ski treadmill tests, on-snow maximal speed tests, and strength/power tests were performed. VO2peak and peak treadmill speed during incremental testing and relative heart rate, rating of perceived exertion, blood lactate concentrations, and gross efficiency during submaximal testing were all significantly correlated with performance in the TT and subsequent finals (mean [range] r values: .67 [.53-.86], all P < .05). Relative VO2peak and submaximal relative heart rate and blood lactate concentration were more strongly correlated with performance in the semifinals and final compared with the TT (r values: .74 [.60-.83] vs 0.55 [.51-.60], all P < .05). Maximal speed in uphill and flat terrain was significantly correlated with performance in the TT and subsequent finals (r values: .63 [.38-.70], all P < .05), while strength/power tests did not correlate significantly with sprint performance. VO2peak and high-speed abilities were the most important determinants of sprint cross-country skiing performance, with an increased importance of VO2peak as the competition format progressed toward the final.

THE EFFECTS OF HYBRID CARDIAC REHABILITATION USING SYNCHRONIZED TELEHEALTH ON PATIENT

https://youtu.be/SCVc_k8SYT4 BACKGROUND Cardiac rehabilitation is effective for secondary prevention of cardiac events and is endorsed by consensus guidelines but is limited by low enrollment and completion rates. Non-traditional delivery models that facilitate participation in CR are needed. The improving ATTENDance (iATTEND) to CR trial is an open label, single-site trial that compared standard facility-based only CR (FBCR) to hybrid CR (HYCR = patient-individualized combination of virtual CR delivered via synchronized telehealth and up to 12 in-facility CR sessions). METHODS Qualifying patients enrolling into early outpatient CR were consented and randomized 1:1 to HYCR (n=142) or FBCR (n=140). Primary outcome was total number of CR sessions completed within 6 mo. Secondary outcomes were percent of patients completing all 36 prescribed CR sessions and changes (after CR – before CR) in exercise capacity (peak oxygen uptake, VO2; 6-minute walk distance, 6MWD). Both attendance outcomes (alpha set at p&amp;lt;0.05) and both exercise capacity outcomes [examined using the TOST (two, one sided tests) equivalence test] were adjusted for relevant, pre-specified co-variates. RESULTS Among patients enrolled into iATTEND (54% Black race, 33%; women, 34% &amp;gt; 65 yr), neither the total number of CR sessions completed per patient (28.7 + 11.8 vs 27.6 + 11.8 visits, adjusted p = 0.41) nor percent of patients completing 36 sessions (58.5 + 4.1 vs 50.7 + 4.2%, adjusted p=0.32) were different between HYCR and FBCR, respectively. After CR, changes in peak VO2 (mL.kg.-1min-1) were 2.3 + 2.8 vs 1.9 + 2.8 (HYCR and FBCR, respectively; adjusted p=0.78) and changes in 6MWD (m) were 46 + 46 vs 55 + 53 (HYCR and FBCR, respectively; adjusted p=0.18); TOST indicated equivalency (p=.001) between groups for both measures of change in exercise capacity. Across 7,735 total CR sessions, there was one major adverse event (non-fatal stroke within 3 hr after CR in HYCR) and no falls requiring medical attention. CONCLUSION In a diverse cohort of patients that included understudied groups, our data suggest that HYCR is an effective non-traditional model to deliver CR. When compared to standard FBCR, HYCR results in similar patient attendance patterns and equivalent improvements in exercise capacity. (Funded by: National Heart, Lung, and Blood Institute)

ARE CHANGE IN METS DURING CARDIAC REHAB RELATED TO CHANGE IN PEAK VO2 AND 6MWD?

https://youtu.be/x7wTd1TmxrA BACKGROUND Change in metabolic equivalents of task (METs) during exercise training is often used as a program outcome in cardiac rehabilitation (CR). The purpose of this study is to assess the correlation between the change in estimated exercise training METs during a CR program and the change in six-minute walk distance (6MWD) and change in peak oxygen uptake (VO2). METHODS This is a secondary analysis of data from the iATTEND trial- a randomized controlled trial that compared facility based CR versus hybrid CR. Subjects included in this analysis had a history of myocardial infraction, coronary revascularization, heart failure, or valve surgery and completed ≥12 sessions of CR. METs during exercise training were estimated using ACSM treadmill equations from the average of the second, third and fourth sessions of CR and the final three sessions of CR. 6MWD and peak VO2 was derived from a symptom limited graded exercise treadmill test with gas exchange were collected at baseline before starting CR and within 14 days of completing CR. Pearson correlation coefficient was determined between change in estimated exercise training METs and both change in 6MWD and in peak VO2. RESULTS The final cohort was n=237 (age=59±12 years; 35% women; 57% non-white race). The correlation between change in estimated exercise training METs and 6MWD was r=0.257, r=0.245, and r=0.235 among patients who completed ≥12 sessions of CR, ≥24 sessions of CR, and 36 sessions of CR, respectively. The correlation between change in estimated exercise training METs and peak VO2 was r=0.121, r=0.100, and r=0.136 among patients who completed ≥12 sessions of CR, ≥24 sessions of CR, and 36 sessions of CR, respectively. CONCLUSIONS Although change in estimated exercise training METs during a CR program, change in 6MWD, and change in peak VO2 have each been used to describe change in exercise tolerance for program outcomes, the association between these variables is low (r= &amp;lt;0.3). This finding was independent regardless of the number of sessions completed. Further research is needed to better understand the relationship between the various methods of assessing change in exercise tolerance and program outcomes in CR.

A COMPARISON OF GUIDELINES FOR HEART TRANSPLANT CONSIDERATION BASED ON CPET DATA

https://youtu.be/tfol-46xG-o BACKGROUND The International Society for Heart and Lung Transplantation (ISHLT) recommends using peak oxygen uptake (VO2≤12 mL/kg/min), percent predicted peak VO2 (ppVO2≤50%), or the ventilation to carbon dioxide slope (VE/VCO2 slope&amp;gt;35) to guide listing for heart transplantation (HTx) in patients with heart failure with reduced ejection fraction (HFrEF). Data comparing the mortality rates between each of these thresholds is lacking. The purpose of this retrospective cohort study was to describe the 3-year mortality rate among patients with HFrEF based on the ISHLT recommendations. METHODS This was a secondary analysis of a combined cohort of patients (≥18 years) with HFrEF from Henry Ford Hospital (n=1,063) and the HF-ACTION study (n=1,772). The cohort was limited to patients who completed a cardiopulmonary exercise test on a treadmill and were prescribed a beta-adrenergic blockade at the time of the test. The primary outcome was probability of all-cause mortality at 3 years based on Kaplan-Meier estimates. Patients were censored at the date of HTx, left ventricular assist device implant, or last known alive. Mortality rates were calculated for patients with a peak VO2≤12 mL/kg/min, ppVO2≤50%, and VE/VCO2 slope&amp;gt;35. The cohort was stratified by sex, age, obesity (body mass index [BMI]&amp;gt; 30 kg/m2), and peak respiratory exchange ratio (RER). Mortality rates were compared to the 3-year mortality post HTx reported by ISHLT. RESULTS In our combined cohort (n=2,775; age=57±13 y; 19% women; 48% non-white), 3-year mortality for peak VO2≤12 mL/kg/min, ppVO2≤50%, and VE/VCO2 slope&amp;gt;35 was 30%, 31%, and 28%, respectively. Each of these are higher than the 3-year mortality post HTx (20%). Similar results were observed by age below/above 50 y, BMI &amp;lt; versus &amp;gt; 30 kg/m2, RER ≤ versus &amp;gt;1.05, and within men. However, among women the 3-year mortality was 18% for peak VO2≤12 mL/kg/min, 25% for ppVO2≤50%, and 21% for VE/VCO2 slope&amp;gt;35. CONCLUSIONS ISHLT recommendations to guide listing for HTx for peak VO2≤12 mL/kg/min, ppVO2≤50%, and VE/VCO2 slope&amp;gt;35 are associated with a higher 3-year mortality than patients post HTx irrespective of age, obesity, and RER. However, among women only ppVO2≤50% and VE/VCO2 slope&amp;gt;35 identify patients with 3-year mortality that is higher than HTx.

Hemodynamic Response to Exercise Training in Heart Failure With Reduced Ejection Fraction Patients.

Supervised exercise training decreases total and cardiac mortality and increases quality of life of heart failure with reduced ejection fraction (HFrEF) patients. However, response to training is variable from one patient to another and factors responsible for a positive response to training remain unclear. The aims of the study were to compare cardiac hemodynamic changes after an exercise training program in responders (R) versus non-responders (NR) HFrEF patients, and to compare different discriminators used to assess response to training. Seventy-six HFrEF patients (86% males, 57 ± 12 years) completed an exercise training program for 4 weeks. Patients underwent cardiopulmonary exercise testing (CPET) on a cycle ergometer before and after training. Cardiac hemodynamics were measured by impedance cardiography during CPET. The R and NR groups were classified using the median change in peak oxygen uptake (V̇O2peak). There were statistically significant differences in V̇O2peak (+35% vs. -1%, P < 0.0001) and in peaks of ventilation (+30% vs. +2%, P < 0.0001), cardiac output (COpeak) (+25% vs. +4%, P < 0.01), systolic blood pressure (+12% vs. +2%, P < 0.05), diastolic blood pressure (+9% vs. +4%, P < 0.05) and heart rate (+8% vs. +1%, P < 0.01) between R and NR after the training program. V̇O2peak was the best discriminator between R and NR (receiver operating characteristic (ROC) area under the curve (AUC) = 0.83, P < 0.0001), followed by COpeak (ROC AUC = 0.77, P < 0.0001). V̇O2peak is the best discriminator between HFrEF R and NR patients after the training program. Responders showed improvements in peak hemodynamic parameters. These results pave the way for other studies to determine how the individualization of exercise training programs and peak hemodynamic parameters potentially linked to a better positive response status.

The intensity paradox: A systematic review and meta-analysis of its impact on the cardiorespiratory fitness of older adults.

The present systematic review and meta-analysis aimed to compare the effect of moderate- versus high-intensity aerobic exercise on cardiorespiratory fitness (CRF) in older adults, taking into account the volume of exercise completed. The databases MEDLINE (Ovid), EMBASE (Ovid), and CENTRAL (Cochrane Library) were searched to identify randomized controlled trials (RCTs). Two reviewers extracted data and assessed bias. Comprehensive Meta-Analysis software calculated overall effect size, intensity differences, and performed meta-regression analyses using pre-to-post intervention or change scores of peak oxygen uptake (V̇O2 peak). The review included 23 RCTs with 1332 older adults (intervention group: n = 932; control group: n = 400), divided into moderate-intensity (435 older adults) and high-intensity (476 older adults) groups. Meta-regression analysis showed a moderate, but not significant, relationship between exercise intensity and improvements in V̇O2 peak after accounting for the completed exercise volume (β = 0.31, 95% CI = [-0.04; 0.67]). Additionally, studies comparing moderate- versus high-intensity revealed a small, but not significant, effect in favor of high-intensity (Hedges' g = 0.20, 95% CI = [-0.02; 0.41]). Finally, no significant differences in V̇O2 peak improvements were found across exercise groups employing various methods, modalities, and intensity monitoring strategies. Findings challenge the notion that high-intensity exercise is inherently superior and indicate that regular aerobic exercise, irrespective of the specific approach and intensity, provides the primary benefits to CRF in older adults. Future RCTs should prioritize valid and reliable methodologies for monitoring and reporting exercise volume and adherence among older adults.

Shifting the Energy Toward Los Angeles: Comparing the Energetic Contribution and Pacing Approach Between 2000- and 1500-m Maximal Ergometer Rowing.

To compare the energetic contribution and pacing in 2000- and 1500-m maximal rowing-ergometer performances. On separate visits (>48 h apart, random order), 18 trained junior (16.7 [0.4]y) male rowers completed 3 trials: a7 × 4-minute graded exercise test, a2000-m time trial (TT2000), and a1500-m TT (TT1500). Respiratory gases were continuously measured throughout each trial. The submaximal power-to-oxygen-consumption relationship from the graded exercise test was used to determine the accumulated oxygen deficit for each TT. Differences in mean power output (MPO), relative anaerobic contribution, percentage of peak oxygen uptake, pacing index, maximum heart rate, rating of perceived exertion, and blood lactate concentration were assessed using linear mixed modeling. Compared to TT2000 (324 [24]W), MPO was 5.2% (3.3%) higher in TT1500 (341 [29W]; P < .001, ηp2=.70). There was a 4.9% (3.3%) increase (P < .001, ηp2=.71) in anaerobic contribution from 17.3% (3.3%) (TT2000) to 22.2% (4.3%) (TT1500). Compared to TT1500, maximum heart rate, rating of perceived exertion, and blood lactate concentration were all greater (P < .05) in TT2000. The pacing index was not different between trials. Percentage increase in MPO from TT2000 to TT1500 was negatively associated with pacing variance in TT1500 (R2 = .269, P = .027). Maximal ergometer performance over 1500m requires a significantly greater anaerobic contribution compared with 2000m. Junior male athletes adopt a consistent pacing strategy across both distances. However, those who experienced greater percentage increases in MPO over the shorter test adopted a more even pacing strategy. To prepare for 1500-m performance, greater emphasis should be placed on developing capacity for work in thesevere domain and completing race simulations with a more even pacing strategy.

Exploring the role of sex in the association of late chronotype on cardiorespiratory fitness.

Circadian rhythms differ between young adult males and females. For example, males tend to be later chronotypes, preferring later timing of sleep and activity, than females. Likewise, there are sex differences in body composition and cardiorespiratory fitness. Few studies have investigated the association between circadian rhythms, cardiorespiratory fitness, and body composition. We sought to determine whether chronotype and circadian phase were associated with cardiorespiratory fitness, body composition, and anthropometric measures in sedentary males and females. Fifty-nine adults participated in the study. Circadian phase and chronotype were measured using dim light melatonin onset (DLMO) and the Morningness-Eveningness Questionnaire (MEQ) score. We used peak oxygen uptake (VO2peak ) results from a maximal graded exercise test to assess cardiorespiratory fitness. Body composition, BMI, and circumferences were collected as markers of adiposity. We observed a sex difference in the association between DLMO and VO2peak . For males, a later DLMO was associated with a lower VO2peak . VO2peak did not vary based on DLMO in females. Later circadian phase was also associated with increased body fat percentage, fat mass index, and abdominal circumference in males, but not females. Collectively, these results suggest that males who are later chronotypes may be at risk of obesity and low cardiorespiratory fitness.

The effect of exercise training intervention for patients with abdominal aortic aneurysm on cardiovascular and cardiorespiratory variables: an updated meta-analysis of randomized controlled trials

ObjectiveThe purpose of this meta-analysis was to evaluate the effect of exercise training intervention in patients with abdominal aortic aneurysm (AAA).MethodsEight randomized controlled trials (RCTs) that recruited 588 AAA patients were extracted using 4 databases (PubMed, Embase, Wanfang Data, and Cochrane Library). Physiological and biochemistry parameters that included in this study are high-sensitivity C-reactive protein (hs-CRP), respiratory peak oxygen uptake rate (VO2peak), triglyceride (TG), total cholesterol (TC), anaerobic threshold (AT), the diameter of AAA, high density lipoprotein cholesterol (HDL), low density lipoprotein cholesterol (LDL), and matrix metalloproteinase-9 (MMP-9). Standard mean difference (SMD) was used to assess the between group effect.ResultsThis meta-analysis was synthesized with findings from RCTs and found that hs-CRP (SMD, − 0.56 mg/dL; 95% CI: − 0.90 to 0.22; P = 0.001), VO2peak (SMD, 0.4 mL/kg/min; 95% CI, 0.21 to 0.60; P < 0.001), TG (SMD, − 0.39 mg/dL; 95% CI: − 0.02 to 0.77; P = 0.04), and AT (SMD, 0.75 mL/kg/min; 95% CI, 0.54 to 0.96; P < 0.001) were significantly improved in the exercise groups, while the size of AAA (SMD, − 0.15; 95% CI: − 0.36 to 0.06; P = 0.15), TC (SMD, 0.16 mg/dL; 95% CI: − 0.10 to 0.42; P = 0.23), HDL/LDL ratio (SMD, − 0.06; 95% CI: − 0.32 to 0.20; P = 0.64), HDL (SMD, − 0.09; 95% CI: − 0.39 to 0.20; P = 0.54), LDL (SMD, 0.08; 95% CI: − 0.21 to 0.38; P = 0.59), and MMP-9 (SMD, − 0.23 mg/dL; 95% CI: − 0.53 to 0.06; P = 0.12) did not differ in the exercise groups compared with the controls.ConclusionExercise intervention improved some of the CVD risk factors but not all, hs-CRP, VO2peak and AT were significantly improved after exercise intervention, while, changes of MMP-9, the size of AAA, and the overall lipids profile were not. Exercise intervention provides an additional solution for improving cardiorespiratory capacity and health status among AAA patients, and might lead to a delay of AAA progression.

A Comprehensive Assessment of the Chinese Version of the Duke Activity Status Index in Patients with Cardiovascular Diseases.

Exercise capacity serves as a direct representation of cardiac function. The Duke Activity Status Index (DASI), a self-administered 12-item questionnaire, covers aspects of daily living, household tasks, sexual function, and physical activity. Although widely used to evaluate exercise capacity, its validation in Chinese cardiovascular disease (CVD) patients has not been thoroughly explored. Considering the significant cultural and lifestyle differences between China and Western countries, which may influence Chinese patients' comprehension and responses to DASI, our objective is to culturally adapt DASI for Chinese patients with CVD to ensure its precision in assessing exercise capacity. The cultural adaptation of the original DASI questionnaire into Chinese followed a rigorous process to ensure its validity, reliability, and sensitivity to Chinese CVD patients. The study included 107 outpatients diagnosed with CVD who completed the DASI and cardiopulmonary exercise testing (CPET). Cronbach's alpha, Spearman correlation, and factor analysis were utilized to test reliability and validity. Receiver operating characteristic (ROC) curve analysis was employed to assess the prognostic utility of the DASI. Participants had a mean DASI score of 39.40 10.75 and a peak oxygen uptake (Peak ) of 19.53 5.89 mL/min/kg. The Chinese version of the DASI exhibited satisfactory reliability and validity in CVD patients, with a Chronbach's alpha coefficient of 0.706. The DASI score demonstrated a moderate correlation with Peak measured by CPET (r = 0.67, p 0.001). Factor analysis yielded three factors, accounting for 56.76% of the total variance, with factor 1 contributing to 26.38% of the variance. ROC curve analysis demonstrated that the DASI exhibited discriminative utility in the identification of patients with improved long-term prognosis (p 0.001). The ROC curve had an area of 0.788 [95% confidence interval (CI) = 0.704-0.871]. The DASI score 36.85 served as the optimal threshold for enhanced long-term prognosis, exhibiting a sensitivity of 0.80 and a specificity of 0.69. The culturally adapted DASI questionnaire is a straightforward and efficient tool for reasonably evaluating exercise capacity in Chinese CVD patients.

Below or all the way to the peak? Oxygen uptake efficiency slope as the index of cardiorespiratory response to exercise-the NOODLE study.

Background: The ratio of oxygen uptake (VO2) to minute ventilation (VE) is described as the oxygen uptake efficiency slope (OUES). OUES has been suggested as a valuable submaximal cardiorespiratory index; however, its characteristics in endurance athletes remain unknown. In this study, we a) investigated OUES between different time intervals, b) assessed their prediction power for VO2peak, and c) derived new prediction equations for OUES tailored for well-trained individuals. Materials and Methods: A total of 77 male (age = 21.4 ± 4.8yrs; BMI = 22.1 ± 1.6kg·m-2; peak oxygen uptake = 4.40 ± 0.64L·min-1) and 63 female individuals (age = 23.4 ± 4.3yrs; BMI = 23.1 ± 1.6kg·m-2; peak oxygen uptake = 3.21 ± 0.48L·min-1) underwent the cycling cardiopulmonary exercise test. OUES was measured at 75%, 90%, and 100% of exercise duration. Prediction power and new models were derived with the multiple linear regression method. Results: In male subjects, OUES [mL·min-1/L·min-1] from 75% = 4.53 ± 0.90, from 90% = 4.52 ± 0.91, and from 100% = 4.41 ± 0.87. In female subjects, OUES [mL·min-1/L·min-1] from 75% = 3.50 ± 0.65, from 90% = 3.49 ± 0.62, and from 100% = 3.41 ± 0.58. OUES did not differ between time intervals in male (p = 0.65) and female individuals (p = 0.69). OUES strongly predicts peak VO2 independently from the measuring interval (β = 0.71-0.80; R 2 = 0.50-0.63). The prediction model designed for elite athletes was OUES [mL·min-1/L·min-1] = -1.54 + 2.99; BSA [m2]-0.0014; (age [in years]; sex [1 = male, 2 = female]) (R 2 = 0.36). Conclusion: OUES enables an accurate prediction of peak cardiorespiratory fitness in elite endurance athletes. OUES is a feasible alternative to maximal exercise testing. A new prediction equation should be used for highly trained individuals. Physicians should understand OUES physiology to properly assess the cardiorespiratory response to exercise in athletic cohorts.

Longitudinal strain and myocardial work in symptomatic patients having recovered from COVID-19 and possible associations with the severity of the disease.

COVID-19 may have residual consequences in multiple organs, including the cardiovascular system. The purpose of the present investigation is to quantify myocardial function in symptomatic individuals with long COVID and investigate the association between illness severity and myocardial function. A retrospective cross-sectional study was conducted in which symptomatic individuals with previous COVID-19 underwent echocardiographic analysis of left ventricle global longitudinal strain (LVGLS) and myocardial work (MW). Individuals also performed cardiopulmonary testing (CPX) to assess peak oxygen uptake (VO2peak). Differences between illness severity subgroups were analyzed by the Mann-Whitney test. Correlations were calculated using the Spearman correlation test. Multilinear regressions were performed to evaluate the influences of COVID-19 severity, body mass index, age, and sex on MW. Fifty-six individuals were included (critical subgroup: 17; moderate/severe subgroup: 39), 59% females; median age: 56years (IQR: 43-63). CPX revealed a substantial reduction in VO2peak (median of 53% of predicted values). LVGLS were not statistically different between subgroups. Global wasted work (GWW) was higher in the critical subgroup [146 (104-212) versus 121 (74-163) mmHg%, p = 0.01], and global work efficiency (GWE) was lower in this subgroup [93 (91-95) versus 94 (93-96), p = 0.03]. Illness severity was the only independent predictor of GWW and GWE (GWW: r2 = 0.167; p = 0.009; GWE: r2 = 0.172; p = 0.005) in multilinear regressions. In our study with long COVID-19 individuals, despite having a similar LVGLS, patients had subclinical LV dysfunction, demonstrated only by an increase in GWW and a decrease in GWE.

Effectiveness of a dose-graded aerobic exercise regimen on cardiopulmonary fitness and physical performance in pediatric survivors of acute lymphoblastic leukemia: a randomized clinical trial.

To determine whether a 12-week supervised dose-graded aerobic exercise (D-GAE) training, when implemented in conjunction with traditional rehabilitation, could help pediatric survivors of acute lymphoblastic leukemia (ALL) enhance their cardiopulmonary capacity and improve their physical performance. Fifty-eight pediatric survivors of ALL (age 13.78 ± 2.47years; boys 60.34%) were assigned at random to either undergo the D-GAE in addition to the traditional physical rehabilitation (D-GAE group; n = 29) or the traditional physical rehabilitation solely (control group; n = 29). The cardiopulmonary fitness (peak oxygen uptake (VO2peak), ventilatory equivalent (VEq/VO2), minute ventilation (VE, L/min), oxygen pulse (O2P), maximum heart rate (HRmax), 1-min heart rate recovery (HRR1), and respiratory exchange ratio (RER)) and physical performance (6-min walk test (6-MWT), timed up and down stairs (TUDS), and 4 × 10-m shuttle run test (4 × 10mSRT)) were assessed on the pre- and post-intervention occasions. The mixed-model ANOVA revealed a meaningful increase of VO2peak (P = .002), VE (P = .026), O2P (P = .0009), HRmax (P = .004), and HRR1 (P = .011), and reduction of VEq/VO2 (P = .003) and RER (P = .003) in the D-GAE group compared with the control group. Besides, the analysis detected a favorable increase in the physical performance for the D-GAE group (6-MWT (P = .007), TUDS (P < .001), 4 × 10mSRT (P = .009)). A 12-week D-GAE program in conjunction with traditional rehabilitation holds promise in enhancing cardiopulmonary fitness and improving the physical performance of pediatric survivors of ALL. Clinicians and physical rehabilitation professionals can, therefore, integrate the D-GAE into the traditional rehabilitation protocols for such a patient population to optimize their cardiopulmonary fitness and physical function, while also facilitating a gradual transition to practice and adaption. The favorable outcomes of this study bolster the inclusion of D-GAE as a crucial element in the care and rehabilitation of pediatric survivors of ALL. By embracing these findings, healthcare professionals and oncologists can contribute to mitigating the long-term cardiopulmonary and physical complications associated with cancer treatments and fostering a state of enhanced well-being and increased physical activity among survivors.

Recreational futsal provides broad-spectrum fitness and health benefits but no blood pressure effects in men with treated hypertension – a randomised controlled trial

ABSTRACT We determined the coadjuvant effect of a recreational futsal (RF) programme versus standard care alone (CON) in men with treated arterial hypertension (TAHT). Thirty-nine men with TAHT were randomised to RF (N = 20; 48 ± 8 years; systolic blood pressure [SBP]: 122 ± 14 mmHg) with 2–3 one-hour sessions/week for 3 months, or to CON (N = 19; 51 ± 6 years; SBP: 126 ± 13 mmHg). Participants were assessed at baseline, at 3 months, and after 1 month of training cessation (4 months). Mean training attendance was 60 ± 23%. At 3-months, there were no between-group differences in BP parameters (SBP: 0.44 mmHg; 95% CI: −5.79, 6.67). However, compared to CON, RF was effective for peak oxygen uptake (2.76 mL.min−1.kg−1; 95% CI: 0.26, 5.26), time to exhaustion (1.15 min; 95% CI: 0.59, 1.69), Yo-Yo IE1 performance (365 m; 95% CI: 175, 556), resting heart rate (RHR; −5 b.min−1; 95% CI: −10, −1), glycated haemoglobin (−0.52 mmol/L; 95% CI: −0.84, −0.19), blood glucose (−0.25 mmol/L; 95% CI: −0.44, −0.06), left femur bone mineral content (1.96 g; 95% CI: 0.29, 3.65), and postural balance (−2.3 falls; 95% CI: −3.9, −0.6). Similar findings were observed after 1-month of training cessation, except for RHR and blood glucose that returned to baseline levels in the RF group. In conclusion, RF provides broad-spectrum fitness and health benefits but no BP effects in men with TAHT.