Cycle Ergometer Exercise Research Articles

Identification of heart rate dynamics during treadmill and cycle ergometer exercise: the role of model zeros and dead time

Background The response of heart rate to changes in exercise intensity is comprised of several dynamic modes with differing magnitudes and temporal characteristics. Investigations of empirical identification of dynamic models of heart rate showed that second-order models gave substantially and significantly better model fidelity compared to the first order case. In the present work, we aimed to reanalyse data from previous studies to more closely consider the effect of including a zero and a pure delay in the model. Methods This is a retrospective analysis of 22 treadmill (TM) and 54 cycle ergometer (CE) data sets from a total of 38 healthy participants. A linear, time-invariant plant model structure with up to two poles, a zero and a dead time is considered. Empirical estimation of the free parameters was performed using least-squares optimisation. The primary outcome measure is model fit, which is a normalised root-mean-square model error. Results A model comprising parallel connection of two first-order transfer functions, one with a dead time and one without, was found to give the highest fit (56.7 % for TM, 54.3 % for CE), whereby the non-delayed component appeared to merely capture initial transients in the data and the part with dead time likely represented the true dynamic response of heart rate to the excitation. In comparison, a simple first-order model without dead time gave substantially lower fit than the parallel model (50.2 % for TM, 47.9 % for CE). Conclusions This preliminary analysis points to a linear first-order system with dead time as being an appropriate model for heart rate response to exercise using treadmill and cycle ergometer modalities. In order to avoid biased estimates, it is vitally important that, prior to parameter estimation and validation, careful attention is paid to data preprocessing in order to eliminate transients and trends.

A novel risk score based on exercise capacity to predict all-cause mortality in adults with congenital heart disease

Abstract Background Impaired exercise capacity in adults with congenital heart disease is associated with mortality. Thus, exercise capacity is a potential tool for predicting risk in this population. The present study attempts to further explore the usefulness of exercise capacity in risk assessment of all-cause mortality, together with a limited number of easily accessible clinical variables. Methods The national register of congenital heart disease was searched for adults (18-60 years of age) with at least one bicycle ergometer exercise test and follow up in the register. The exercise capacity was classified based on percent of predicted exercise capacity (EC%pred); normal (> 70%), moderately impaired (50-70%) or severely impaired (<50%). All patients were followed for 10 years or until death, if occurring earlier than 10 years after the exercise test. Data were analyzed using logistic regression modelling. A risk evaluation model was constructed based on percent of predicted exercise capacity, age, and complexity of the heart lesion. Finally, the model was converted into a 5-point (p) risk score used to predict 10-year mortality (EC%pred >70%=0p, 50-70=1p, <50%=2p, age <25=0p, 25-40=1p, 40-60=2p, simple lesion=0p, moderate/severe complexity of heart lesion=1p). Results 1171 patients (mean age at exercise test 30.5 years, 44% women) were included with 70 deaths occurring within 10 years. A score 0-1 corresponded to <1% 10-year all-cause mortality, 2p 5%, 3p 9%, 4p 21% and 5p 33% mortality risk (Table 1). The area under curve for the model was 0.75 (95% CI 0.69-0.81). Conclusion An easily performed risk assessment containing % of predicted exercise capacity, age and complexity of heart lesion performs well in detecting patients at both low and high risk of all-cause mortality within 10 years after an exercise test.

An alternate to accumulated oxygen deficit (AOD) for measuring anaerobic contribution: 'AOD_alt' is valid in normoxia and hypoxia.

The gold standard measure of anaerobic contribution is accumulated oxygen deficit (AOD). The purpose of this study was to investigate the validity of an alternate measure, AOD_alt. AOD_alt is the sum of the phosphocreatine and glycolytic contributions, which are estimated from post-exercise oxygen uptake and blood lactate concentration, respectively. In Study One, six women and three men performed 6-min bouts of heavy intensity cycle ergometer exercise, once in normoxia (FIO2 ~ 21%) and twice under hypoxic conditions (FIO2 ~ 15% and ~ 12%). In Study Two, four women and two men performed severe intensity tests to exhaustion, once in normoxia (~ 10min) and twice in hypoxia (FIO2 ~ 15% and ~ 10%). Physiological responses were measured during exercise and 7min of recovery. In 6min of heavy exercise, Study One, the alternate and criterion measures of anaerobic contribution (AOD_alt and AOD) were correlated, in normoxia and in hypoxia. In exhaustive severe exercise, Study Two, AOD_alt and AOD were correlated (r = 0.77) and similar, in normoxia and at FIO2 ~ 15%. However, AOD_alt and AOD values were neither correlated (r = 0.27) nor similar (57 ± 5mL·kg-1 vs 51 ± 7mL·kg-1) at FIO2 ~ 10%. These results confirm the validity of AOD_alt as a measure of anaerobic capacity in severe intensity exercise, demonstrate its validity in heavy exercise, and assert its validity in conditions of hypoxia (FIO2 ~ 12%).

Whole body sweat rate prediction: indoor treadmill and cycle ergometer exercise.

This article describes the development and validation of accurate whole body sweat rate prediction equations for individuals performing indoor cycle ergometer and treadmill exercise, where power output can be measured or derived from simple inputs. For cycle ergometry, 112 trials (67 participants) were used for model development and another 56 trials (42 participants) for model validation. For treadmill exercise, 171 trials (67 participants) were used for model development and another 95 trials (63 participants) for model validation. Trials were conducted over a range of dry-bulb temperature (20°C to 40°C), relative humidity (14% to 60%), and exercise intensity (∼40% to 85% of peak aerobic power) conditions, which were matched between model development and model validation. Whole body sweat rates were measured, and proprietary prediction models were developed (accounting for all relevant biophysical factors) and then validated. For model validation, mean absolute error for predicted sweating rate was 0.01 and 0.02 L·h-1 for cycle and treadmill trials, respectively. The 95% confidence intervals were modest for cycle ergometer (+0.25 and -0.22 L·h-1) and treadmill exercise (+0.33 and -0.29 L·h-1). The accounted for variance between predicted and measured values was 92% and 78% for cycle and treadmill exercise, respectively. Bland-Altman analysis indicated that zero and one predicted value exceeded the a priori acceptable level of agreement (equivalent to ±2% of total body mass in 3 h) for cycle and treadmill exercise, respectively. There were fewer trials with female subjects, but their values did not differ from those expected for males. This is the foremost study to develop and validate whole body sweat rate prediction equations for indoor treadmill and cycle ergometer exercise of moderate to high intensity. These prediction equations are publicly available for use (https://sweatratecalculator.com).NEW & NOTEWORTHY This study presents the development of new proprietary whole body sweat rate prediction models for people exercising indoors on a cycle ergometer or treadmill using simple input parameters and delivered through a publicly available online calculator: https://sweatratecalculator.com. In an independent validation group, the predictive models for both indoor cycling and treadmill exercise were accurate across moderate to high exercise intensities in temperate to hot conditions. These equations will enable individualized hydration management during physical training and exercise physiology experiments.

Effect of low-intensity aerobic cycling ergometer on ability to perform activity of daily living of patients with myasthenia gravis in RSUD Dr. Soetomo Surabaya

Background and objectives. Myasthenia gravis (MG) is an autoimmune disease of the neuromuscular junction causing fluctuating skeletal muscle weakness and fatigue that result in increased restrictions on physical activity, affecting the patient's ability to perform daily activities in the family, social, and work environment. The MG-ADL scale is an assessment of the ability of the daily activities of MG patients that does not require equipment or special skills for the examiner and can be done in a short time. This study analyzes the effect of low intensity aerobic exercise cycle ergometer on the ability to perform daily activities of MG patients. Materials and methods. Twenty-two MG patients, MGFA class IIa and IIb, aged 18–59, participated in this study. The subjects were randomly divided into a treatment group and a control group. The treatment group received aerobic cycle ergometer exercise for 30 minutes, three times per week, for eight weeks. Both groups were educated to continue medication from neurology, perform physical activity as usual, and breathing exercises. Assessment of MG-ADL performed before and after intervention. Results. There was an improvement in scores on breathing and lower limb function in the treatment group. There was significant decrease in MG-ADL scores at the intervention group (p = 0.000) with large effect size (1.09). The comparison of MG-ADL scores between groups showed a significant value (p = 0.009) with a large effect size (1.24). Conclusion. Low intensity aerobic exercise cycle ergometer for 8 weeks improves the ability to perform ADL in MG patient.

Low-intensity aerobic cycle ergometer effects on lung function of myasthenia gravis patients: A randomized controlled trial

Patients with generalized myasthenia gravis (MG) often show restrictive spirometry results. Although regular exercise and physical fitness are linked to better respiratory function, there is limited research assessing the effects of aerobic exercise on lung function in MG patients. The aim of this study was to analyze the effect of low-intensity aerobic exercise using a cycle ergometer on lung function parameters in MG patients. A randomized controlled trial with pre- and post-test was conducted at the Medical Rehabilitation Outpatient Clinic of Dr. Soetomo General Academic Hospital in Surabaya, Indonesia, in 2023. MG patients classified as I−IIb based on the Myasthenia Gravis Foundation of America (MGFA) classification were recruited and randomly divided into treatment and control groups. The treatment group was given low-intensity aerobic exercise using a cycle ergometer, education on lifestyle changes, and breathing exercises (deep and pursed lip breathing). Lung function parameters, including forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), and forced expiratory volume ratio (FEVR), were then measured. Measurements were conducted before and after eight weeks of low-intensity aerobic cycle ergometer exercise and compared with those of a control group. A total of 17 MG patients were included in this study. The results showed a significant increase in FVC in the treatment group (p=0.003), whereas no significant change in the control group (p=0.068). A significant increase in FEV1 was observed both in the treatment (p=0.029) and the control group (p=0.016). There was no improvement in FEVR in either group. After the intervention, significant differences were observed in FVC (p=0.009) and FEV1 (p=0.029) between the treatment and control groups. There was no significant difference in FEVR values after the intervention between both groups (p=0.491). In conclusion, eight weeks of low-intensity aerobic cycle ergometer exercise led to significant improvements in FVC and FEV1 among MG patients.

Revealing the unrevealed: echocardiography for non-ischemic scar tissue detection.

The detection of myocardial scar tissue profoundly influences athletes care and prognostic categorization. Athletes appear to be at risk of developing fatal arrhythmias when harboring a quiescent cardiac disorder. Early identification of disease in asymptomatic individuals through preparticipation screening is means to prevent these events. We presented a male marathon runner master athlete who came at our Department of Sports Medicine for a preparticipation screening. Baseline 12-lead standard electrocardiogram was normal. A maximal cycle ergometer exercise test revealed exercise-induced premature ventricular contractions (PVCs) with uncommon morphology. Echocardiography revealed an hyperechogenic zone at mid-basal posterior segments of the left ventricle. Twenty-four-hours ECG Holter monitoring, with training session, showed some isolated polymorphic PVCs even during training session. Cardiac magnetic resonance (CMR) confirmed the presence of a non-ischemic left ventricular scar (subepicardial) into the mid-basal segment of the posterior wall. Echocardiography is a first-line, economic, and accessible diagnostic test for athletes and it can be useful, when abnormalities are detected, to indicate further investigations, such as CMR. Although non-ischemic left ventricular scarring is difficult to detect on echocardiography, this event is sometimes possible and require further investigation when observed.

The Responsiveness of Exercise Tests in COPD: A Randomized Controlled Trial

BackgroundChronic obstructive pulmonary disease (COPD) is characterised by reduced exercise tolerance and improving physical performance is an important therapeutic goal. A variety of exercise tests are commonly used to assess exercise tolerance, including laboratory and field-based tests. The responsiveness of these tests to common COPD interventions is yet to be compared, but may inform test selection in clinical and research settings. Research QuestionWhat exercise test possesses the greatest sensitivity to change pre- to post-intervention in patients with COPD? Study Design and Methods154 patients with symptomatic COPD were recruited and randomised (2:1:1) to six weeks of long-acting muscarinic antagonist (LAMA), pulmonary rehabilitation (PR), or usual care (UC). Pre- and post-intervention, participants performed a ramp-incremental and constant work rate cycle ergometer exercise test (ICET and CWRCT), incremental and endurance shuttle walk test (ISWT and ESWT), six-minute walk test (6MWT), and a four metre gait speed test (4MGS). Results103 participants (67 ± 8 y; 75 [73%] males; FEV1: 50.6 ± 16.8 % predicted) completed the study. Significant improvements in the ICET, CWRCT, ISWT, ESWT, and 6MWT were observed following PR (p<0.05), with the greatest improvements seen in the constant work rate protocols (% change: CWRCT: 42%; ESWT: 41%). InterpretationThe ESWT and CWRCT appeared to be the most responsive exercise test protocols to LAMA and PR. The magnitude of change was much greater after a programme of rehabilitation compared to bronchodilator therapy.

Exercise Intolerance in McArdle Disease: A Role for Cardiac Impairment? A Preliminary Study in Humans and Mice.

Whether cardiac impairment can be fully discarded in McArdle disease-the paradigm of 'exercise intolerance', caused by inherited deficiency of the skeletal muscle-specific glycogen phosphorylase isoform ('myophosphorylase')-remains to be determined. Eight patients with McArdle disease and seven age/sex-matched controls performed a 15-minute moderate, constant-load cycle-ergometer exercise bout followed by a maximal ramp test. Electrocardiographic and two-dimensional transthoracic (for cardiac dimension's assessment) and speckle tracking [for left-ventricle global longitudinal (GLS) assessments] echocardiographic evaluations were performed at baseline. Electrocardiographic and GLS assessments were also performed during constant-load exercise and immediately upon maximal exertion. Four human heart biopsies were obtained in individuals without McArdle disease, and in-depth histological/molecular analyses were performed in McArdle and wild-type mouse hearts. Exercise intolerance was confirmed in patients ('second wind' during constant-load exercise, -55% peak power output vs controls). As opposed to controls, patients showed a decrease in GLS during constant-load exercise, especially upon second wind occurrence, but with no other between-group difference in cardiac structure/function. Human cardiac biopsies showed that all three glycogen phosphorylase-myophosphorylase, but also liver and especially brain-isoforms are expressed in the normal adult heart, thereby theoretically compensating for eventual myophosphorylase deficiency. No overall histological (including glycogen depots), cytoskeleton, metabolic or mitochondrial (morphology/network/distribution) differences were found between McArdle and wild-type mouse hearts, except for lower levels of pyruvate kinase M2 and translocase of outer membrane 20 kDa subunit in the former. This study provides preliminary evidence that cardiac structure and function seem to be preserved in patients with McArdle disease. However, the role for an impaired cardiac contractility associated with the second wind phenomenon should be further explored.

The Influence of Acute Oral Lactate Supplementation on Responses to Cycle Ergometer Exercise: A Randomized, Crossover Pilot Clinical Trial.

The purpose of this study was to investigate the potential ergogenic effects of an oral lactate supplement. For this double-blind, randomized, placebo-controlled crossover design, fifteen recreational exercisers (nine males, six females) ingested a placebo or a commercially available lactate supplement prior to cycle ergometer exercise. Primary outcomes included peak oxygen uptake (VO2peak; via indirect calorimetry), VO2 at the ventilatory threshold, and work rate at the lactate threshold (arterialized venous blood from a heated hand) determined during incremental exercise to fatigue, and power output during a 20-min cycling time trial. Compared with placebo, the oral lactate supplement (19 ± 1 mg/kg body mass) did not influence VO2peak (placebo: 44.3 ± 7.8 vs. oral lactate: 44.3 ± 7.1 mL/kg/min (mean ± SD); p = 0.87), VO2 at the ventilatory threshold (placebo: 1.63 ± 0.25 vs. oral lactate: 1.65 ± 0.23 L/min; p = 0.82), or work rate at the lactate threshold (placebo: 179 ± 69 vs. oral lactate: 179 ± 59 W; p = 0.41). Throughout the 20-min time trial, the work rate was slightly greater (4%) with oral lactate (204 ± 41 W) compared with placebo (197 ± 41 W; main effect of treatment p = 0.02). Collectively, these data suggest that this commercially available lactate supplement did not acutely influence the physiological responses to incremental cycle ergometer exercise but elicited a modest ergogenic effect during the short-duration time trial.

Effects of intradialytic bicycle ergometer exercise on transcription factors NF-ĸB and Nrf2 in patients with chronic kidney disease: A randomized crossover clinical trial

PurposeTo evaluate the effects of an intradialytic aerobic exercise training program on the expression of transcription factors nuclear factor κappa B (NF-κB) and nuclear factor erythroid 2-related factor 2 (Nrf2), related to inflammatory and antioxidant pathways, respectively, in patients with chronic kidney disease (CKD) on hemodialysis. MethodsThis was a longitudinal, randomized clinical trial with a washout period and crossover performed with 33 patients randomized into two groups: Exercise (individualized intradialytic aerobic exercise on an adapted stationary exercise bike) three times per week for three months and control (without exercise). After the washout period (1 month), the exercise group became the control, and the other group performed the exercises for another three months. Blood sample collection, food intake, and anthropometry were evaluated at the beginning and end of each study phase. Nrf2, its target gene NAD(P)H quinone oxidoreductase 1 (NQO1), and NF-κB transcription factors were evaluated by quantitative real-time polymerase chain reaction (qRT-PCR) and the inflammatory cytokines tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) by ELISA assay. ResultsEighteen patients [11 men, 44.1 ± 8.4 years, 17.3 (6.6–124) months on HD] completed all the study. The obtained data revealed that the intervention did not affect Nrf2, NQO1, and NF-κB mRNA expression. Also, TNF-α levels were not changed. However, IL-6 showed a tendency to decrease after the exercise intervention (p = 0.054). ConclusionIn hemodialysis patients, three months of intradialytic aerobic exercise did not modulate the transcription factors associated with inflammation (NF-κB) and antioxidant activity (Nrf2 and NQO1). Clinical trials registration numberNCT04375553.

Identification of heart rate dynamics during treadmill and cycle ergometer exercise: the role of model zeros and dead time

Background The response of heart rate to changes in exercise intensity is comprised of several dynamic modes with differing magnitudes and temporal characteristics. Investigations of empirical identification of dynamic models of heart rate showed that second-order models gave substantially and significantly better model fidelity compared to the first order case. In the present work, we aimed to reanalyse data from previous studies to more closely consider the effect of including a zero and a pure delay in the model. Methods This is a retrospective analysis of 22 treadmill (TM) and 54 cycle ergometer (CE) data sets from a total of 38 healthy participants. A linear, time-invariant plant model structure with up to two poles, a zero and a dead time is considered. Empirical estimation of the free parameters was performed using least-squares optimisation. The primary outcome measure is model fit, which is a normalised root-mean-square model error. Results A model comprising parallel connection of two first-order transfer functions, one with a dead time and one without, was found to give the highest fit (56.7 % for TM, 54.3 % for CE), whereby the non-delayed component appeared to merely capture initial transients in the data and the part with dead time likely represented the true dynamic response of heart rate to the excitation. In comparison, a simple first-order model without dead time gave substantially lower fit than the parallel model (50.2 % for TM, 47.9 % for CE). Conclusions This preliminary analysis points to a linear first-order system with dead time as being an appropriate model for heart rate response to exercise using treadmill and cycle ergometer modalities. In order to avoid biased estimates, it is vitally important that, prior to parameter estimation and validation, careful attention is paid to data preprocessing in order to eliminate transients and trends.

Cardiopulmonary haemodynamics in Tibetans and Han Chinese during rest and exercise.

During sea-level exercise, blood flow through intrapulmonary arteriovenous anastomoses (IPAVA) in humans without a patent foramen ovale (PFO) is negatively correlated with pulmonary pressure. Yet, it is unknown whether the superior exercise capacity of Tibetans well adapted to living at high altitude is the result of lower pulmonary pressure during exercise in hypoxia, and whether their cardiopulmonary characteristics are significantly different from lowland natives of comparable ancestry (e.g. Han Chinese). We found a 47% PFO prevalence in male Tibetans (n=19) and Han Chinese (n=19) participants. In participants without a PFO (n=10 each group), we measured heart structure and function at rest and peak oxygen uptake ( ), peak power output ( ), pulmonary artery systolic pressure (PASP), blood flow through IPAVA and cardiac output ( ) at rest and during recumbent cycle ergometer exercise at 760Torr (SL) and at 410Torr (ALT) barometric pressure in a pressure chamber. Tibetans achieved a higher than Han, and a higher at ALT without differences in heart rate, stroke volume or . Blood flow through IPAVA was generally similar between groups. Increases in PASP and total pulmonary resistance at ALT were comparable between the groups. There were no differences in the slopes of PASP plotted as a function of during exercise. In those without PFO, our data indicate that the superior aerobic exercise capacity of Tibetans over Han Chinese is independent of cardiopulmonary features and more probably linked to differences in local muscular oxygen extraction. KEY POINTS: Patent foramen ovale (PFO) prevalence was 47% in Tibetans and Han Chinese living at 2275m. Subjects with PFO were excluded from exercise studies. Compared to Han Chinese, Tibetans had a higher peak workload with acute compression to sea level barometric pressure (SL) and acute decompression to 5000m altitude (ALT). Comprehensive cardiac structure and function at rest were not significantly different between Han Chinese and Tibetans. Tibetans and Han had similar blood flow through intrapulmonary arteriovenous anastomoses (IPAVA) during exercise at SL. Peak pulmonary artery systolic pressure (PASP) and total pulmonary resistance were different between SL and ALT, with significantly increased PASP for Han compared to Tibetans at ALT. No differences were observed between groups at acute SL and ALT.

Effects of Acute Beetroot Juice Supplementation and Exercise on Cardiovascular Function in Healthy Men in Preliminary Study: A Randomized, Double-Blinded, Placebo-Controlled, and Crossover Trial.

Nitrate-rich beetroot juice (NRBRJ) can potentially enhance exercise performance and improve cardiovascular function, leading to an increased use of NRBRJ over the years. However, the combined effects of NRBRJ supplementation and exercise on cardiovascular function remain unclear. Therefore, this study compared cardiovascular function responses to submaximal exercise with either placebo (PLA) or NRBRJ supplementation in healthy men. Twelve healthy men (aged 25.2 ± 2.3 years) completed the 30-min submaximal cycle ergometer exercise trials corresponding to 70% maximal heart rate (HRmax) with either PLA or NRBRJ supplementation in a random order. The mean exercise load, heart rate (HR), stroke volume (SV), cardiac output (CO), systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), and total peripheral resistance (TPR) were measured during exercise. The brachial-ankle pulse wave velocity (baPWV) and flow-mediated dilation (FMD) were measured before and after exercise. NRBRJ supplementation was more effective than PLA in increasing the mean exercise load and decreasing DBP and MAP during submaximal exercise. Furthermore, baPWV decreased in the NRBRJ trial and was considerably lower after exercise in the NRBRJ-supplemented group than in the PLA-supplemented group. FMD significantly increased in the PLA and NRBRJ trials; however, NRBRJ supplementation demonstrated a significantly higher FMD before and after exercise than PLA supplementation. In conclusion, acute NRBRJ supplementation and exercise were more effective than PLA supplementation and exercise in improving aerobic exercise capacity and cardiovascular function in healthy men.

Assessment of Maximal Oxygen Uptake (VO2 Max) in Athletes and Nonathletes Assessed in Sports Physiology Laboratory.

Athletes' physical prowess plays a crucial role in their ability to succeed in any sporting endeavor. Each athlete on the field must have an exceptional aerobic capacity to withstand fierce competition and stringent regulatory guidelines.Maximal oxygen uptake (VO2max) is a quantitative measure of aerobic capacity and is regardedas one of themost reliable indicators ofcardiorespiratory and overall physical fitness of an individual by sports physiologists. The study aims to evaluate the VO2 max of athletes in comparison with nonathletes during treadmill and lower limb cycle ergometry exercises as assessed in the Sports Physiology Laboratory of a rural medical college.Treadmill exercise and bicycle ergometer exercise are the most common to perform as indoor aerobic exercises to assess one's physical fitness. Both these tests are equally useful in eliciting cardiac and vascular responses, so both these modalities were used to assess aerobic fitness. This cross-sectional study, which examined participants aged 17-25, included 30 athletes (cases) and 120 age- and sex-matched controls. The VO2 max was evaluated using the Metabolic Module of Lab Chart Software, which was investigated through the PowerLab data acquisition system, AD Instruments (Bella Vista,NSW, Australia). The mean age of male athletes was 20.51 ± 2.69 years and of female athletes was 20.53 ± 1.62 years. The mean and standard deviation of VO2 max on the treadmill for male cases was 52.37 ± 8.78 mL/kg/min and for female cases was 40.96 ± 4.06 mL/kg/min, and on a cycle ergometer for male cases was 45.21 ± 9.43 mL/kg/min and for female cases was 34.32 ± 5.12 mL/kg/min. For the control group, the mean age of control males was 21.2 ± 2.62 years and of control females was 20.36 ± 1.5 years. The mean and standard deviationof VO2 max on the treadmill for control males was 33.35 ± 3.77 mL/kg/min and for control females was 25.09 ± 7.07 mL/kg/min, and on the cycle ergometer for control males was 34.17 ± 2.75 mL/kg/min and for control females was 24.15 ± 5.35 mL/kg/min. This study showed significantly (p < 0.001) higher VO2 max levels in athletes of both genders compared to their age- and sex-matched controls upon exercise on the treadmill and cycle ergometer. This study underscores the significance of better cardiorespiratory fitness in athletes than nonathletes, giving pertinent insights about their aerobic capacity, which is precisely measured and expressed in terms of VO2.

The Affective Responses to Moderate Physical Activity: A Further Study to Prove the Convergent and the Discriminant Validity for the German Versions of the Feeling Scale and the Felt Arousal Scale.

The present study proves the construct validity of the German versions of the Feeling Scale (FS) and the Felt Arousal Scale (FAS) for measuring the affective responses (affective valence and arousal) for a moderate-intensity jogging (JG) exercise. In previous studies, both scales were validated for a high-intensity bicycle ergometer exercise and for relaxation techniques. In the present study, 194 participants performed the JG exercise for 45 min and completed the FS and the FAS, as well as the Self-Assessment Manikin (SAM), for a self-other comparison in a pre-test-intervention-post-test design. The results of the correlation analyses replicated the previous findings for the high-intensity bicycle ergometer exercise and the relaxation techniques, revealing significant positive correlations for the valence dimension between the FS and the SAM-Pleasure subscale (r = 0.50) and for the arousal dimension between the FAS and the SAM-Arousal subscale (r = 0.16). These findings suggest that the German versions of the FS and the FAS are also suitable for exercises of moderate intensity.

Characterizing Heart Rate Variability Response to Maximal Exercise Testing in People with Huntington's Disease.

Huntington's disease (HD) is an autosomal dominant, neurodegenerative disease that involves dysfunction in the autonomic nervous system (ANS). Heart rate variability (HRV) is a valid and noninvasive measure for ANS dysfunction, yet no study has characterized HRV response to exercise in people with HD. Characterize HRV response to exercise in individuals with HD and explore its implications for exercise prescription and cardiac dysautonomia mechanisms. 19 participants with HD were recruited as part of a cohort of individuals enrolled in the Physical Activity and Exercise Outcomes in Huntington's Disease (PACE-HD) study at Teachers College, Columbia University (TC). 13 non-HD age- and gender-matched control participants were also recruited from TC. HRV was recorded with a Polar H10 heart rate (HR) monitor before, during, and after a ramp cycle-ergometer exercise test. Participants with HD showed reduced HR peak (p < 0.01) and HR reserve (p < 0.001) compared with controls. Participants with HD demonstrated reduced root mean square of successive differences between normal-to-normal intervals (RMSSD) and successive differences of normal-to-normal intervals (SDSD) at rest (p < 0.001). Participants with HD also showed differences for low frequency (LF) power (p < 0.01), high frequency (HF) normalized units (nu) (p < 0.05), LF (nu) (p < 0.001), and HF/LF ratio (p < 0.05) compared with controls. We found reduced aerobic exercise capacity and sympathovagal dysautonomia both at rest and during post-exercise recovery in people with HD, suggesting modified exercise prescription may be required for people with HD. Further investigations focusing on cardiac dysautonomia and underlying mechanisms of sympathovagal dysautonomia in people with HD are warranted.

Estimating maximum work rate during cardiopulmonary exercise testing from the six-minute walk distance in patients with heart failure

BackgroundExercise is recommended for patients with chronic heart failure (CHF) and its intensity is usually set as a percentage of the maximal work rate (MWR) during cardiopulmonary exercise testing (CPX) or a symptom-limited incremental test (SLIT). As these tests are not always available in cardiac rehabilitation due to logistic/cost constraints, we aimed to develop a predictive model to estimate MWR at CPX (estMWR@CPX) in CHF patients using anthropometric and clinical measures and the 6-min walk test (6 MWT), the most widely used exercise field test. MethodsThis is a multicentre cross-sectional retrospective study in a cardiac rehabilitation setting. Six hundred patients with HF in New York Heart Association (NYHA) functional class I-III underwent both CPX and 6 MWT and, through multivariable linear regression analysis, we defined several predictive models to define estMWR@CPX. ResultsThe best model included 6 MWT, sex, age, weight, NYHA class, left ventricular ejection fraction (LVEF), smoking status and chronic obstructive pulmonary disease COPD (adjusted R2 = 0.55; 95% LoA −39 to 33 W). When LVEF was excluded as a predictor, the resulting model performed only slightly worse (adjusted R2 = 0.54; 95% LoA −42 to 34 W). Only in 34% of cases was the percentage difference between estMWR@CPX and real MWR@CPX <10% in absolute value. EstMWR@CPX tended to overestimate low values and underestimate high values of true MWR@CPX. ConclusionsOur results showed a lack of accuracy in the predictive model evaluated; therefore, for an accurate prescription of cycle-ergometer exercise training, it is necessary to assess MWR by CPX or SLIT.

FEASIBILITY OF AEROBIC FITNESS TESTING IN AMNESTIC MILD COGNITIVE IMPAIRMENT FROM THE ACT TRIAL

Abstract Aerobic fitness has been postulated as a physiological mechanism of action for aerobic exercise to modify Alzheimer’s disease, but it has not been adequately studied in older adults with (MCI). The purpose of this study is to evaluate the feasibility of a gold-standard, laboratory-based, symptom-limited cycle-ergometer exercise testing (GXT) in older adults with amnestic mild cognitive impairment (aMCI) to assess peak oxygen consumption (VO2max [ml/kg/min]) using baseline data from the ACT Trial. The test was categorized as a submax, near-max, and max test based on if 0, 1, and ≥2 of the American College of Sports Medicine criteria was met: &amp;gt;90% of age-predicted maximum heart rate, plateau in VO2Peak, respiratory exchange ratio &amp;gt;1.10, and rating of perceived exertion &amp;gt;17. VO2max was predicted as 3.5*maximal metabolic equivalents (METs). Among 146 enrolled participants (73.8±5.7 years old with 16.9±2.9 years of education, 51.4% men, and 91.8% Caucasian), 145 completed GXTs. Sixteen GXTs (11.0%) were submax (VO2Peak 13.5±4.4), 53 (36.6%) were near-max (VO2Peak 16.5±4.1), and 76 (52.4%) were max (VO2Peak 18.4±5.1). Predicted VO2max were 21.6±6.8, 28.7±26.3, and 30.0±20.5 from submax, near-max, and max tests, respectively. Among max GXTs, VO2max was 19.5±4.9 in men (n=37) and 17.4±5.1 in women (n=39). In conclusion, GXTs was feasible for ~52% of the participants. METs-based prediction overly inflates VO2max estimates, in comparison to VO2max obtained from max GXTs. VO2max levels are substantially lower in older adults with aMCI than peers (23.1±6.3 in men and 21.1±3.4 in women), suggesting aerobic exercise as an important intervention for this population.

People with obesity exhibit losses in muscle proteostasis that are partly improved by exercise training.

This pilot experiment examines if a loss in muscle proteostasis occurs in people with obesity and whether endurance exercise positively influences either the abundance profile or turnover rate of proteins in this population. Men with (n=3) or without (n=4) obesity were recruited and underwent a 14-d measurement protocol of daily deuterium oxide (D2O) consumption and serial biopsies of vastus lateralis muscle. Men with obesity then completed 10-weeks of high-intensity interval training (HIIT), encompassing 3 sessions per week of cycle ergometer exercise with 1min intervals at 100% maximum aerobic power interspersed by 1min recovery periods. The number of intervals per session progressed from 4 to 8, and during weeks 8-10 the 14-d measurement protocol was repeated. Proteomic analysis detected 352 differences (p<0.05, false discovery rate<5%) in protein abundance and 19 (p<0.05) differences in protein turnover, including components of the ubiquitin-proteasome system. HIIT altered the abundance of 53 proteins and increased the turnover rate of 22 proteins (p<0.05) and tended to benefit proteostasis by increasing muscle protein turnover rates. Obesity and insulin resistance are associated with compromised muscle proteostasis, which may be partially restored by endurance exercise.