Cycle Ergometer Test Research Articles

Gender-related dynamics of exercise tolerance in patients with acute coronary syndrome undergoing the outpatient phase of rehabilitation

Background. The relevance of the comparative study of exercise tolerance in male and female cardiac patients is due to the need to individualize physical rehabilitation programs.
 Aims: to study the impact of gender on exercise tolerance in patients with acute coronary syndrome undergoing a course of rehabilitation in a day hospital.
 Methods. 110 patients with acute coronary syndrome were examined: 81 men (73.6%) aged 34 to 75 years and 29 women (26.4%) aged 44 to 74 years. In accordance with the purpose of the study, all patients were exposed to stress testing before and after the end of the three-week rehabilitation course.
 Results. According to the analysis of the six-minute walk test and the Bicycle ergometric test, men had better physical endurance than women. Features of hemodynamic indicators during physical activity also correlate with gender: in comparison with men, the maximum physical load in women was accompanied by higher heart rate values. At the end of the rehabilitation course, women had a more pronounced improvement of Bicycle ergometry indicators: a greater increase in maximum power and the percentage of load performed during the test.
 Conclusions. The gender differences in exercise tolerance in cardiac patients identified in the study should be taken into account when designing rehabilitation programs.

Physiological Responses of Youth Players During Wheelchair Basketball Games

The purpose of this study was to document physiological responses that result from participation in youth wheelchair basketball (WCB) games. Each participant (4 males, 2 females, mean age = 15.2 y, SD= 1.8 y) completed a peak aerobic capacity upper-body cycle ergometer test until fatigue. Additionally, each participant competed in two regular season youth WCB games while wearing a Polar Pro Team System heart rate (HR) monitor. During competition, average HR, peak heart rate (HRpeak), playing intensity, total distance covered, training load score, and caloric expenditure were recorded. Results from the study indicated a HR mean = 140.8 b×min-1, SD = 19.8 b×min-1, HRpeak mean = 188.9 b×min -1, SD= 15.8 b×min-1, and mean = 83.3%, SD = 13.7% level of exercise intensity from participation in the two games. Additionally, participation in WCB games revealed that players traversed mean= 909.4 meters, SD= 230.4 meters, achieved a training load score mean = 120.3, SD= 65.2, and expended mean = 718.2 calories, SD = 184.5 calories, across the two games. In conclusion, participation by adolescents in a WCB game meets the physiological demands needed to achieve health-related fitness benefits established by both the American College of Sports Medicine and the Centers for Disease Control and Prevention.

Validity Of Combined Heart Rate And Accelerometry To Predict Activity Energy Expenditure In Older Adults

PURPOSE: The present study compared physical activity related energy expenditure (PAEE) as predicted by group calibrated algorithm combining accelerometry and heart rate. METHODS: N=45 older adults with and without cardiac risk performed a protocol consisting of simulated daily living activities (resting period, light, moderate and vigorous physical activity including walking in different speeds and stair climbing) and a cycle ergometer test (25W + 25W every 2 minutes). PAEE was concurrently assessed by indirect calorimetry (IC) and by combined heart rate (HR) plus uniaxial accelerometry (ACC). Raw HR and ACC data were transformed to PAEE using a published branched equation model. Estimated and measured PAEE were compared using Bland-Altman plots. SUMMARY OF RESULTS: Preliminary results of n=12 healthy older adults without cardiac risk (8 male and 4 female, 71.9 ± 5.2 years) showed lower ACC+HR-estimated PAEE for clustered activities (including cycle ergometer test) and resting period (clustered activities 2.17 ± 1.17 Kcal/min; resting period 0.19 ± 0.17 Kcal/min) than PAEE measured by IC (clustered activities 2.93 ± 1.27 Kcal/min; resting period 0.61 ± 0.40 Kcal/min). The Bland & Altman plots' limits of agreement were between -2.28 and +0.94 kcal/min. Visual inspection showed that the dispersion of the absolute differences between ACC+HR and IC seemed to increase with higher measured values. The correlation between combined ACC+HR-PAEE and IC-PAEE was rρ = 0.86. CONCLUSION: First results indicate that branched equation models based on combined ACC+HR registrations may underestimate PAEE in older people but appear sufficiently valid for the assessment of mean PAEE in groups. If the relatively large limits of agreement were to persist throughout this ongoing study, they would indicate a limited validity of existing ACC+HR branched equations for the individual assessment of PAEE in older adults. More research is needed to determine whether combined ACC+HR assessments are superior to simple ACC to measure physical activity in older adults.

Validating sweat ammonia as physiological parameter for wearable devices in sports science.

The measurement of physiological parameters in sweat has long been assumed to offer a non-invasive alternative to conventional blood testing. Recently, advances in sensor technology enable the production of printed sweat sensors applicable for the use in wearable devices. However, the remaining challenge is the determination of the physiological correlation between blood and sweat components. In this study, we conducted ammonia measurements in blood and sweat during a stepwise incremental cycle ergometer test in 40 subjects under completely controlled conditions in a clinical environment to determine the correlation between the ammonium concentrations in blood and sweat. Samples were taken for each workload step separately. Sweat was sampled directly from the upper body, blood was taken from an indwelling cannula at the end of each workload step, respectively. For meaningful classification of the measured quantities, blood lactate and heart rate were monitored additionally. The results for blood ammonium concentration show increasing behavior in good accordance with the established indicators for physical exhaustion, whereas sweat ammonium concentration seems to decrease with workload. This is found to be due to dilution, as sweat rate increases. The presented results provide insight in the correlation between blood and sweat parameters and therefore are of high importance for further development of wearable devices.Clinical Relevance-Sweat sensing opens up new possibilities for non-invasive, continuous in-situ monitoring of physiological parameters for healthcare and sports science applications.

Blood Pressure, Fitness, And Fatness In Children The Arkansas Active Kids Study

PURPOSE: The role of cardiorespiratory fitness (CRF) in pediatric health is gaining recognition. However, the quality and quantity of the current evidence are insufficient to inform clinical pediatric guidelines. Objective: to evaluate the association between direct measures of CRF and blood pressure status as determined by the 2017 screening guidelines from the American Academy of Pediatrics in school-age children. METHODS: Children (n=218) 7 to 10 years old participated in a single-study visit. Children were deemed to have high blood pressure (HBP) if blood pressure status was: elevated, stage-1 or stage-2 hypertension. CRF (V02peak) was measured using an incremental cycle ergometer test. Body composition was measured with DXA, and physical activity with accelerometers (7±1 days). Blood was sampled in the fasting state and estimated glomerular filtration rate (eGRF) calculated using the updated Schwartz equation. Children were categorized as having excess weight (EW) or normal weight (NW) if their fat mass index was above or below 1 z-score, respectively. Children were further classified into EW/NW more-fit or EW/NW less-fit using the groups’ median VO2peak. Multiple logistic regression analyses were used to model the probability of high blood pressure against VO2peak. RESULTS: Participants’ average age was 9 years, with 70% of EW children having HBP vs. 24% in the NW group (p<.0001). The probability of HBP decreased with increasing VO2peak in the EW group only (β=0.09, p=0.0095). There was no association between CRF and probability of HBP in NW children. eGFR was lower in the less-fit groups than in more-fit groups regardless of adiposity status, even after adjusting for age and blood pressure status (adjusted mean difference between more-fit and less-fit groups: EW=7.1 ml·min-1·1.73 m-2, p=0.0046 and NW= 2.9 ml·min-1·1.73 m-2p=0.0144). CONCLUSION: The probability of HBP dramatically decreases with increasing CRF in children with EW but not in children with NW. eGFR is lower in children with lower CRF, regardless of obesity status, but the effect of CRF on and kidney function is greater in EW than in NW kids. Funding USDA-ARS Projects 59-6250-4-001 and 6026-51000-012-06S. ECD partially supported by ArCAPT-8UG1OD024945.

Audience Presence Prolongs Maintenance Of Peak Power In Maximal Anaerobic Activity

Sport participation commonly occurs in front of an audience. It is important to know if the presence of that audience influences the force profile of the performer. PURPOSE: To examine the influence of spectator presence on power output in a short-duration, high-intensity activity. METHODS: We tested 15 men and 28 women, ages 18-25, on a 30-second Wingate cycle ergometer test. All subjects were tested twice, separated by 72 hours. During one trial, performance took place in front of the test administrator; during the other trial, the administrator was accompanied by an audience. Spectators observed but did not interact with the subjects. Testing conditions (e.g., time of day, instructions provided, and verbal encouragement) were identical in the two trials. The order of tests was assigned in a counter-balanced design. Mixed ANOVA with repeated measures was used to compare peak power (PP), duration of peak power (DPP), and mean power (MP) between the two trials overall and by sex. RESULTS: Subjects were 20.4 ± 1.4 years of age; across all testing, PP 1.7 ± 1.3 w/kg, DPP was 2.6 ± 3.5 seconds, and mean power was 1.2 ± 0.3 w/kg. There was no effect of test order on performance (p=0.199). Similarly, there was no effect of audience presence on PP (p=0.348) or an interaction effect with sex (p=0.406). There was an increase in MP in the audience trial; subjects were 0.1 w/kg higher, corresponding to a 6.5% increase (p=0.003; 95% CI: 0.03 to 0.13 w/kg). There was no interaction effect with sex (p=0.416). The increase in MP was the result of an increase in DPP, which was 1.6 seconds longer in the audience trial, corresponding to a 91.6% increase (p=0.002; 95% CI: 0.61 to 2.49 seconds). There was no interaction effect with sex (p=0.418). CONCLUSIONS: The presence of an audience influenced power output on the Wingate test. Although peak power was unaffected, the duration peak power was maintained nearly doubled, indicating endurance at peak performance may be sensitive to arousal.

Does Exercise Choice Matter For Cardiorespiratory Fitness Improvements?

Low cardiorespiratory fitness (CRF) is an important risk factor for cardiometabolic disease and individuals with prediabetes tend to have low CRF. Trials that have compared High-Intensity Interval Training(HIIT) to Moderate-Intensity Continuous Training(MICT) by imposingindividuals to HIIT or MICT haveestablished that HIIT is effective for improving CRF. However, to maintain these improvements, individuals need to adhere to HIIT. Self-determination theory states that providingchoicehas a positive impact on exercise adherence. PURPOSE:To address whether having the choice to engage in HIITor MICT for 6-months (CHOICE) leads to greater changes in CRF (absolute and relative VO2peak) at 6-months when compared to IMposed HIIT (IM-HIIT)or IMposed MICT (IM-MICT) in adults with prediabetes. METHODS: In this single-site randomized trial, 68 low-active adults (56.8±6.6 yrs, mean±SD) living with prediabetes were randomized to CHOICE (n=24), IM-HIIT (n=21), or IM-MICT (n=23). After an initial supervised training period (6 sessions over 3 weeks) participants exercised unsupervised on their own in free-living conditions for 6 months. A ramp increase cycle ergometer test to exhaustion was conducted by the same technician pre- and post-testing to determine VO2peak. Missing data was accounted for using linear interpolations generated with SPSS®v.20.0. RESULTS: ANCOVA results with baseline CRF as a covariate revealed no significant differences between increases in absolute VO2peak (CHOICE: 0.38, 95% CI; 0.20, 0.55, vs. IM-HIIT: 0.56, 95% CI; 0.37, 0.74 vs. IM-MICT: 0.30, 95% CI; 0.12, 0.48 L/min, F2,64=1.99, P=.14), with similar findings for relative VO2peak (F2,67=0.32, P=.73). Within group changes over time indicated small effect sizes (Hedge’s g) for increases in absolute (CHOICE= 0.00; HIIT = 0.26; and MICT=0.01) and relative VO2peak over time (CHOICE = 0.11; HIIT = 0.33; and MICT=0.15). CONCLUSION:Changes in CRF between groups randomized to perform HIIT or MICT, or given the choice of HIIT or MICT, were not significantly different at 6-months post-intervention. Providing choice for selecting HIIT or MICT did not appear to enhance the benefits of exercise for improving fitness in low active adults. Supported by the Research Endowment from the American College of Sports Medicine Foundation.

The Associations Of Mitochondrial Content And Maximal Oxygen Uptake

INTRODUCTION: The purpose of this study was to explore the relationship between human fiber type specific mitochondria volume density and VO2max. METHODS: Eleven recreational active subjects (VO2max mean 4.54±0.58 L/min) reported to lab for a progressive ergometer cycle test to estimate VO2max. Ten muscle fibers were obtained in each 9 biopsies in vastus lateralis from each of the 11 subjects. In each fibers, 24 images where obtained in a randomized systematic order, thus 528 fibers and 13968 images were analyzed. Point counting was used to estimate imtermyofibrillar (IMF) mitochondrial content as a volume density and subsarcolemmal (SS) mitochondrial content as a volume per fiber surface. Total mitochondrial content were obtained by recalculating the SS subfraction to myofibrillar volume density. Fibre type was determined by z-disk widths. Lean body mass(LBM) was determined by DXA. All data are presented are means ± SD. Associations was evaluated using Pearson´s correlation coefficient. RESULTS: The total, IMF and SS mitochondrial content in type1 are 0.087±0.021 μm3·μm-3, 0.065±0.014 μm3·μm-3, 0.451±0.159 μm3·μm-2, respectively, and in type2 are 0.059±0.018 μm3·μm-3, 0.046±0.012 μm3·μm-3, 0.271±0.129μm3·μm-2, respectively. Total mitochondrial volume content was a strong predictor of VO2max per LBM. Further, IMF mitochondrial content is a better predictor of a subject’s VO2max per LBM than SS mitochondrial content. The fiber type specific correlations revealed that, total, IMF and SS in different fiber types are associated with VO2max per LBM, except SS mitochondrial content in type2 is not associated (Fig 1). CONCLUSION: There is a strong correlation between mitochondrial content and VO2max per LBM, however, VO2max and relative VO2max are not associated with mitochondrial content. Also, there is a clear correlation between total and IMF mitochondrial content and VO2max per LBM in both type 1 and type 2 fibers, whole this was only the case for SS in type 1 fibers.

Relationship between aerobic fitness, blood pressure and life satisfaction

Background: ‪The aim of this work was to examine the extent to which cardiorespiratory fitness, blood pressure, and optimism/pessimism predict adults’ satisfaction with life. Material and methods: ‪Sixty-eight adults seeking cardiovascular health screening in a private clinic were tested. Participants’ blood pressure, optimism/pessimism, and satisfaction with life were recorded. The YMCA cycle ergometer test was used for estimating participants’ aerobic fitness (VO2 max). Based on 140/90 mm Hg blood pressure cut-off value, participants were classified into two groups. Results: ‪A bootstrapped hierarchical multivariate regression analysis revealed that VO2 max, systolic blood pressure, optimism, and pessimism jointly accounted for 46% of the variance (R2 = 0.501, R2 adjusted = 0.462) in life satisfaction. Furthermore, a bootstrapped multivariate analysis of covariance indicated that Stage 2 hypertensives reported lower life satisfaction (p = 0.007) than the others with lower blood pressure readings. Conclusions: ‪This study is the first to reveal that almost half of the total variance in life satisfaction is accounted by cardiorespiratory fitness, systolic blood pressure, optimism, and pessimism. The present work also shows that individuals in Stage 2 hypertension are less satisfied with their lives than individuals with lower blood pressure values. These preliminary findings should stimulate both epidemiological and longitudinal research in the area.

Does Cardiorespiratory Fitness Buffer Stress Reactivity and Stress Recovery in Police Officers? A Real-Life Study.

High levels of cardiorespiratory fitness have the potential to buffer against physical and mental health impairments, which can result from exposure to occupational stress. Police officers are especially at risk of high psychosocial stress; therefore, effective intervention strategies are warranted. Given this background, the purpose of the present study was to examine whether police officers with different levels of cardiorespiratory fitness differ with regard to their (a) physiological stress reactivity during acute real-life stress situations, and (b) physiological recovery related to acute and chronic work stress. In total, 201 police officers took part in this study (M = 38.6 years, SD = 10.1, 35.8% females). Officers were contacted eight times on a smartphone during their workday, and asked to report their current level of positive and negative affect, as well as feelings of stress and anger. Physiological stress responses and recovery (heart rate variability) were assessed using Movisens EcgMove3 devices. The Åstrand bicycle ergometer test was used to assess participants' cardiorespiratory fitness. Chronic work stress was assessed using the effort-reward imbalance model and the job strain model. Multilevel modeling was used to test buffering effects of cardiorespiratory fitness on physiological stress reactivity. Linear regression was applied to test stress-buffering effects of cardiorespiratory fitness on physiological recovery. Results showed lowered physiological stress reactivity to acute work stress in officers with higher levels of cardiorespiratory fitness. However, these results were not consistent, with no effects occurring for feelings of anger, positive affect, and negative affect. Chronic work stress (effort-reward imbalance) was related to lower physiological recovery. Cardiorespiratory fitness was positively related to physiological recovery. Data did not support interactions between work stress and cardiorespiratory fitness on physiological recovery. To some extent, cardiorespiratory fitness seems to have the potential to buffer stress reactivity in police officers in acute stress situations. Therefore, we encourage promoting fitness programs which aim to enhance cardiorespiratory fitness in stressful occupations such as law enforcement. Improvements in cardiorespiratory fitness might further enhance physiological recovery from chronic work stress, which is thought to improve cardiovascular health.

Exercise Training Effects on the Relationship of Physical Function and Health-Related Quality of Life Among Older Heart Failure Patients With Preserved Ejection Fraction.

Although exercise training (ET) has been shown to improve both physical function and health-related quality of life (HRQOL) in older patients with heart failure and preserved ejection fraction (HFpEF), the relationship between changes in these important patient-centered outcome measures has not been adequately investigated. Patients (n = 116) with HFpEF (from 2 previous randomized controlled trials) were assigned to either 16 wk of endurance ET or attention control (CON). The ET in both trials consisted of ≤ 60 min of moderate-intensity endurance ET 3 time/wk. Peak exercise oxygen uptake (V˙o2peak) and other exercise capacity measures were obtained from a cardiopulmonary exercise test on an electronically braked cycle ergometer and 6-min walk test (6MWT). HRQOL was assessed using the Minnesota Living with Heart Failure (MLHF) Questionnaire and the 36-item Short Form Health Survey (SF-36). Compared with CON, the ET group demonstrated significant improvement in measures of physical function (V˙o2peak and 6MWT) at 16 wk of follow-up. There were no significant differences observed between the groups for MLHF scores, but the ET group showed significant improvements on the SF-36. There were no significant correlations between change in any of the physical function and HRQOL measures in the ET group. While endurance ET improved both physical function and some domains of HRQOL, the lack of significant correlations between changes in these measures suggests the effects of ET on physical function and HRQOL are largely independent of one another. Since these measures assess important and unique patient-centered outcomes in HFpEF patients, both physical function and HRQOL should be assessed in exercise-based programs and clinical trials.

Association between cardiorespiratory fitness and social cognition in healthy adults

Whereas there is compelling evidence for an association between cardiorespiratory fitness (CRF) and executive function and attention, its relation with social cognition has not been investigated yet. However, social cognition is linked with mental health and career success in jobs with high demands on social interaction. The present study aims to examine the association between CRF and the facial emotion recognition aspect of social cognition in police officers. The study utilized a cross-sectional design. 198 male and female participants (aged 38.3±1.3years) completed the Åstrand submaximal bicycle ergometer test and their CRF was estimated using the Åstrand-Rhyming nomogram. Additionally, a 2-choice reaction time task and two facial emotion recognition tasks (labeling and matching) with low (emotion recognition from faces) and high (emotion recognition from eyes) difficulty trials were administered for the assessment of attention and social cognition. Adjusting for age, gender, education, and attention, hierarchical regression supported higher CRF to be related to higher performance on overall performance on the facial emotion labeling and matching tasks, Beta=0.141, P=.046. With regard to difficulty levels, a similar association between CRF and task performance was found for the faces condition, Beta=0.147, P=.043, but not for the eyes condition, Beta=0.105, P=.132. Social cognition appears to differ as a function of adults' CRF level. The present findings have a high relevance for police officers, because they need to rely on this cognitive domain for many decisions in their work-life.

Clinical Findings and Return to Work After Heart Valve Replacement

One hundred and thirteen patients operated during the years 1971 to 1976, were re-examined at an average of 26.3 months after heart valve replacement. The functional capacity assessed by the NYHA-classification improved in about 40% of the patients. About 80% considered their symptoms and well-being to have improved after the operation. At the re-examination, heart size was most often enlarged in patients with mitral valve replacement. The average work load measured in bicycle ergometer test was higher in patients with aortic valve replacement compared to those with mitral valve replacement. Patients with aortic valve replacements were working more often (54%) than those with mitral valve replacements (37%). The mean age of patients who were working was significantly lower than in patients who were retired. There was a statistically significant relation between the physical working capacity and the working status. The employability assessed by history and clinical findings corresponded well to the actual work situation in individual patients.

Muscular and cardiorespiratory fitness are associated with health-related quality of life among young adult men

BackgroundDespite numerous studies providing evidence for positive effects of physical activity and physical fitness, evidence for association between physical fitness and health-related quality of life (HRQoL) in young adults is limited. The aim of the present cross-sectional study was to investigate the association of cardiorespiratory and muscular fitness with HRQoL from the perspective of its physical and mental components among young adult Finnish males.MethodsThe sample consisted of 754 men, with the mean age of 26 years (SD 6.7 years), who participated in the military refresher training. HRQoL was measured using the Finnish RAND 36-item health survey. Cardiorespiratory fitness was determined by a bicycle ergometer test, and muscular fitness by various tests measuring maximal strength and muscular endurance. Logistic regression modelling was used to compare low, moderate and high physical and mental component of HRQoL scores to the respective levels of muscular and cardiorespiratory fitness.ResultsThe findings of the adjusted (age, educational level, marital status, employment status, smoking, use of alcohol and BMI) analysis showed that cardiorespiratory and muscular fitness are positively associated with both physical and mental components of HRQoL. In terms of the physical component of HRQoL, even a moderate fitness level was positively associated with better HRQoL. In terms of the mental component of HRQoL, the impact was seen only in the group with the highest fitness level.ConclusionsThe findings suggest a positive contribution of physical fitness to mental health and highlight the importance of both muscular and cardiorespiratory fitness in the promotion of HRQoL. Even lighter forms of physical activity that result in moderate physical fitness could contribute to the physical component of HRQoL. In terms of the mental component of HRQoL, higher levels of physical fitness may be needed to gain higher levels of HRQoL among young males.

A Clinical Method for Estimation of VO2max Using Seismocardiography

The purpose of this study was to investigate the correlation between the seismocardiogram and cardiorespiratory fitness. Cardiorespiratory fitness can be estimated as VO2max using non-exercise algorithms, but the results can be inaccurate. Healthy subjects were recruited for this study. Seismocardiogram and electrocardiogram were recorded at rest. VO2max was measured during a maximal effort cycle ergometer test. Amplitudes and timing intervals were extracted from the seismocardiogram and used in combination with demographic data in a non-exercise prediction model for VO2max. 26 subjects were included, 17 females. Mean age: 38.3±9.1 years. The amplitude following the aortic valve closure derived from the seismocardiogram had a significant correlation of 0.80 (p<0.001) to VO2max. This feature combined with age, sex and BMI in the prediction model, yields a correlation to VO2max of 0.90 (p<0.001, 95% CI: 0.83-0.94) and a standard error of the estimate of 3.21 mL·kg-1·min-1 . The seismocardiogram carries information about the cardiorespiratory fitness. When comparing to other non-exercise models the proposed model performs better, even after cross validation. The model is limited when tracking changes in VO2max. The method could be used in the clinic for a more accurate estimation of VO2max compared to current non-exercise methods.

Are Opera Singers Fit or Not?

Little information is available about the physical fitness of opera singers. The aim of this study is to measure cardiac engagement during rehearsals and to test both cardiovascular fitness and body composition in a group of opera singers. Thirty-two opera singers (17 female and 15 male) were enrolled for the assessment of body composition by bio impedance, of cardiovascular fitness by submaximal exercise test on a cycle ergometer and the physical effort during singing. Anthropometric parameters showed an overweight condition mainly due to an increase in fat mass. Watts reached during the cycle ergometer test were below the normal range for the general population. During rehearsals, singers have reached 95% of the maximum heart rate. Nowadays, opera singers show low levels of physical fitness, but singing is an activity that requires a high heart effort. Therefore, it is recommended to involve such professionals in a gradual and individualized physical training program in order to avoid fatigue during performances and achieve a better singing performance.

The effects of hypoxia on muscle deoxygenation and recruitment in the flexor digitorum superficialis during submaximal intermittent handgrip exercise

BackgroundDecreased oxygenation of muscle may be accentuated during exercise at high altitude. Monitoring the oxygen saturation of muscle (SmO2) during hand grip exercise using near infrared spectroscopy during acute exposure to hypoxia could provide a model for a test of muscle performance without the competing cardiovascular stresses that occur during a cycle ergometer or treadmill test. The purpose of this study was to examine and compare acute exposure to normobaric hypoxia versus normoxia on deoxygenation and recruitment of the flexor digitorum superficialis (FDS) during submaximal intermittent handgrip exercise (HGE) in healthy adults.MethodsTwenty subjects (11 M/9 F) performed HGE at 50% of maximum voluntary contraction, with a duty cycle of 2 s:1 s until task failure on two occasions one week apart, randomly assigned to normobaric hypoxia (FiO2 = 12%) or normoxia (FiO2 = 21%). Near-infrared spectroscopy monitored SmO2, oxygenated (O2Hb), deoxygenated (HHb), and total hemoglobin (tHb) over the FDS. Surface electromyography derived root mean square and mean power frequency of the FDS.ResultsHypoxic compared to normoxic HGE induced a lower FDS SmO2 (63.8 ± 2.2 vs. 69.0 ± 1.5, p = 0.001) and both protocols decreased FDS SmO2 from baseline to task failure. FDS mean power frequency was lower during hypoxic compared to normoxic HGE (64.0 ± 1.4 vs. 68.2 ± 2.0 Hz, p = 0.04) and both decreased mean power frequency from the first contractions to task failure (p = 0.000). Under both hypoxia and normoxia, HHb, tHb and root mean square increased from baseline to task failure whereas O2Hb decreased and then increased during HGE. Arterial oxygen saturation via pulse oximetry (SpO2) was lower during hypoxia compared to normoxia conditions (p = 0.000) and heart rate and diastolic blood pressure only demonstrated small increases. Task durations and the tension-time index of HGE did not differ between normoxic and hypoxic trials.ConclusionHypoxic compared to normoxic HGE decreased SmO2 and induced lower mean power frequency in the FDS, during repetitive hand grip exercise however did not result in differences in task durations or tension-time indices. The fiber type composition of FDS, and high duty cycle and intensity may have contributed greater dependence on anaerobiosis.

Workload-indexed blood pressure response to a maximum exercise test among professional indoor athletes.

Exercise testing is performed regularly in professional athletes. However, the blood pressure response (BPR) to exercise is rarely investigated in this cohort, and normative upper thresholds are lacking. Recently, a workload-indexed BPR (increase in systolic blood pressure per increase in metabolic equivalent of task (SBP/MET slope)) was evaluated in a general population and was compared with mortality. We sought to evaluate the SBP/MET slope in professional athletes and compare it with performance. This was a cross-sectional study. A total of 142 male professional indoor athletes (age 26 ± 5 years) were examined. Blood pressure was measured at rest and during a standardized, graded cycle ergometer test. We assessed the BPR during exercise, the workload, and the metabolic equivalent of task (MET). Athletes were divided into groups according to their SBP/MET slope quartiles (I <4.3; II 4.3-6.2; III >6.2-9; IV >9 mmHg/MET) and compared regarding systolic BP (sBP) and workload achieved. Athletes in group I (n = 42) had the lowest maximum sBP (180 ± 13 mmHg) but achieved the highest relative workload (4.2 ± 1 W/kg). With increasing SBP/MET slope, the maximum sBP increased (II (n = 56): 195 ± 15 mmHg; III (n = 44): 216 ± 16 mmHg) and the workload achieved decreased (II: 3.9 ± 0.7 W/kg; III: 3.3 ± 0.5 W/kg). The differences in sBP between these groups were significant (p < 0.001). None of the athletes were assigned to group IV (>9 mmHg/MET). Athletes in the lowest SBP/MET slope quartile displayed the lowest maximum sBP but achieved a higher workload than athletes classified into the other SBP/MET slope groups. This simple, novel metric might help to distinguish a normal from an exaggerated BPR to exercise, to identify athletes at risk of developing hypertension.

A Pilot Study of Cardiorespiratory Fitness, Adiposity, and Cardiometabolic Health in Youth With Overweight and Obesity.

To conduct a preliminary assessment of the relationships between cardiorespiratory fitness, adiposity, and cardiometabolic health using gold standard measures in diverse youth ranging from overweight to severe obesity. Twenty of 30 participants (mean [SD]; age 13.2 [1.8] y, 55% female, 45% African American) met the criteria for VO2peak during a graded cycle ergometer test to volitional fatigue. The body composition was measured by dual-energy X-ray absorptiometry (percentage of body fat, fat mass index, and fat-free mass) and magnetic resonance imaging (abdominal visceral and subcutaneous [SAT] adipose tissue). The VO2peak was expressed relative to fat-free mass. Fasting lipid levels, glycemic biomarkers, and vital signs were examined individually and used in a composite cardiometabolic risk score. Accelerometer-measured physical activity and sedentary time were included as covariates. VO2peak was negatively associated with abdominal SAT (r = -.49, P < .05), but not visceral adipose tissue or markers of cardiometabolic health. The association between SAT and VO2peak was partly explained by habitual sedentary time. We demonstrated a significant negative association between cardiorespiratory fitness and SAT in a diverse group of high-risk youth. The inclusion of rigorous, laboratory-based measures and youth with severe obesity extends the previous work in pediatric populations.

Effects of hyperoxia on dynamic muscular endurance are associated with individual whole-body endurance capacity.

Low-intensity training involving high repetitions is recommended to enhance muscular endurance. Hyperoxic conditions could increase the number of repetitions until exhaustion and thereby improve the results of muscular endurance training. This study aimed to investigate the acute effects of hyperoxia on dynamic muscular endurance, and determine individual factors that may be related to these effects. A single-blinded, counterbalanced crossover design was used. Twenty-five young men performed repetitions of the one-arm preacher curl at 30% of their 1-repetition maximum until exhaustion under hyperoxic and normoxic conditions. The maximum number of repetitions was recorded as an index of muscular endurance. Electromyogram (EMG) and near-infrared spectroscopy parameters were measured in the biceps brachii. The maximum number of repetitions was greater (P < 0.001) under hyperoxic conditions (132 ± 59 repetitions) than under normoxic conditions (114 ± 40 repetitions). The root mean square amplitude of EMG and oxygenated hemoglobin concentration for the last five repetitions under normoxic conditions were greater than those under hyperoxic conditions (P = 0.015 and P = 0.003, respectively). The percent change in the maximum number of repetitions between hyperoxic and normoxic conditions had significant positive correlations with individual maximal oxygen uptake measured using an incremental cycle ergometer test (r = 0.562, 95% confidence intervals [CI] = 0.213–0.783, P = 0.003), but not with muscle strength (τ = −0.124, 95% CI = −0.424–0.170, P = 0.387). The 95% CI for the correlation coefficient between the percent change in the maximum number of repetitions and muscular endurance included 0 (τ = 0.284, 95% CI = −0.003–0.565, P = 0.047); this indicated no significant correlation between the two parameters. The results suggest that hyperoxia can acutely enhance dynamic muscular endurance, with delayed elevation of EMG amplitude due to fatigue, and the effects are associated with individual whole-body endurance capacity.