Treadmill Cardiopulmonary Exercise Testing Research Articles

Prediction of the burden and characteristics of coronary plaques by cardiorespiratory fitness

Abstract Background Cardiorespiratory fitness (CRF) and coronary plaque burden are both important predictors of mortality. Although mortality of coronary heart disease (CHD) is reduced, prevalence remains high and there is a need to improve early detection and preventive measures. How CRF relates to coronary plaque burden and composition in the general population is largely unknown. Purpose The aim was to study the relationship between CRF and the total coronary plaque burden, including subgroups of coronary plaques, in subjects without known CHD. Methods A random sample of participants from a large population-based echocardiographic reference range study aged 55-70 at baseline was included. Coronary plaque burden was assessed, on average, 4.0 years after the baseline evaluation using coronary computed tomography angiography (CCTA). The burden and characteristics of the coronary plaques were evaluated using a validated, commercially available, semi-automatic software that assessed all coronary territories including the left main, left anterior descending, circumflex, and right arteries. Coronary plaques were classified as dense calcified plaques, plaques with necrotic core, fibrous, and fibrous-fatty plaques. Baseline measures included cardiovascular risk factor assessment and measurement of peak oxygen consumption (VO2peak) assessed by treadmill cardiopulmonary exercise testing. Linear regression models were used to assess the impact of VO2peak on coronary plaque burden. In Model 1, we adjusted for sex and age, while Model 2 also included adjustments for non-HDL cholesterol, HbA1c, systolic blood pressure, smoking status, and body mass index. Results Of 845 invited to undergo CCTA, 707 (51% females) underwent CT scanning. Of these, 699 scans had acceptable quality for further analyses. Table 1 shows baseline characteristics and Table 2 shows the associations of VO2peak with coronary plaque burden. In the fully adjusted Model 2, there was a significant negative association of VO2peak with total plaque burden (β -0.18, R2 15%, p<0.001), while the association was not significant in Model 1 (p=0.54). Similarly, higher VO2peak significantly predicted a lower burden of dense calcified plaques, plaques with necrotic core, and fibrofatty plaques in both models (R2 3-17%, p≤0.01). The results were consistent whether the coronary plaques were evaluated across the entire coronary arteries (down to a diameter of 1.5 mm) or solely in the proximal segments. However, the predictive power of the models was relatively low with R2 of maximum 17%. Conclusion In a population without known CHD, CRF explained a modest part of the variation in coronary plaque burden. Considering CRF in risk prediction may enhance coronary artery disease prevention beyond traditional risk factors.

Peak oxygen pulse response during maximal cardiopulmonary exercise testing on a treadmill: applicability analysis of the FRIEND registry prediction equation in a Brazilian healthy sample

Abstract Background Peak oxygen uptake (VO2peak), measured by cardiopulmonary exercise test (CPET), is an established variable for prognostic assessment. Other VO2peak-derived variables, such as the peak oxygen pulse (peakO2pulse), also provide valuable information for risk stratification in patients with cardiac diseases. For individualized assessment, the measured peakO2pulse can be compared to reference standards using predictive equations, such as the FRIEND Registry [peakO2pulse = 23.2 – (0.09 × Age) – (6.6 × Sex (female:1; male: 0)]. However, the applicabilty of this equation in a Brazilian population sample has never been evaluated. Purpose To conduct an external validation of the FRIEND registry prediction equation for treadmill peakO2pulse in a sample of healthy Brazilian individuals. Methods Cross-sectional study involving subjects assessed by treadmill CPET in the Brazilian Midwest region from January 2011 to March 2020. Inclusion criteria: healthy individuals aged ≥ 20 years with a peak respiratory exchange ratio ≥ 1.00. Exclusion criteria: history of cardiovascular or pulmonary disease, presence of cardiovascular risk factors (hypertension, diabetes mellitus, current smoking, and obesity), and abnormalities on CPET. Variables were described as median and interquartile range (IQR). Statistical comparisons between measured and predicted values were conducted using the Wilcoxon signed rank test, including the calculation of the median differences and the 95% confidence interval (CI). Furthermore, Bland-Altman agreement analysis was utilized to assess the concordance between measured and estimated values. Results A total of 7,843 CPETs were performed. After applying inclusion and exclusion criteria, 3,544 assessments were included (1,574 females and 1,970 males) aged between 20 to 80 years. In the females, the median and IQR of measured peakO2pulse and predicted values were 10.4 (9.0; 12.1) and 13.1 (12.3; 13.7) ml/beat, respectively. This difference was statistically significant (p < 0.001), with a median difference of 2.54 mL/beat (95% CI: 2.40; 2.69). For males, the measured and predicted values were 17.3 (15.1; 19.7) and 19.7 (19.0; 20.2) ml/beat, respectively. The median difference was statistically significant at 2.26 mL/beat (95% CI: 2.11; 2.46) (p < 0.001) (Figure 1). Bland-Altman agreement analysis indicated a bias of 2.33 mL/beat (95% limits of agreement: -2.17 to 6.83) in females and 2.15 mL/beat (95% limits of agreement: -4.34 to 8.65) in males (Figure 2). Conclusions The study reveals that measured median peakO2pulse values are consistently lower than predicted across both sexes, highlighting a significant bias, which limits the applicability of the FRIEND registry prediction equation in the Brazilian population and underscores the international heterogeneity of the variable. The findings advocate for the development of region-specific reference standards to enhance accuracy in predicting peakO2pulse values.

Functional Capacity Assessment in Adults After Fontan Palliation: A Cardiopulmonary Exercise Test–Invasive Exercise Hemodynamics Correlation Study

While cardiopulmonary exercise testing (CPET) parameters have known prognostic value in adults post-Fontan, there is limited data correlating treadmill CPET with invasive exercise hemodynamics. Furthermore, the invasive hemodynamic underpinnings of exercise limitations have not been thoroughly investigated. This is retrospective analysis of 55 adults (≥18 years) post-Fontan who underwent treadmill CPET prior to invasive exercise hemodynamic testing via supine cycle protocol between November 2018 and April 2023. Median age was 32.2 (24.1; 37.2) years. Peak heart rate (HR) was 139.7±28.1 bpm and peak oxygen consumption (VO2) was 19.1±5.7 ml/kg/min (47.4±13.5% predicted). VO2/HR was directly related to exercise stroke volume index (Svi) (r=0.50; p=0.0002), while no association was seen with exercise arterio-mixed venous O2 content difference (r=0.14; p=0.32). Peak HR was inversely related to exercise pulmonary artery (PA) pressures (r=-0 61; p<0.0001) and PA wedge pressures (PAWP) (r=-0.61; p<0.0001). Moreover, % predicted VO2 was inversely related to exercise PA pressures (r=-0.50; p<0.0001) and PAWP (r=-0.55; p<0.0001). Peak VO2 ≤19.1 ml/kg/min had a sensitivity of 81% and specificity of 76% (AUC 0.82) for predicting a ΔPAWP/ΔQs ratio >2 mmHg/l/min and/or a ΔPA/ΔQp ratio >3 mmHg/l/min, while a predicted peak VO2 ≤48% had a sensitivity of 74% and specificity of 81% (AUC 0.79) for the same parameters. In summary, lower peak HR and lower peak VO2 were associated with higher exercise PAWP and PA pressure. Peak VO2 ≤48% predicted provided the optimal cut-off for predicting elevated indexed exercise PAWP or PA pressures, thus low peak VO2 should alert clinicians of abnormal underlying hemodynamics.

Validity of the Ekblom-Bak Cycle Ergometer Test in Patients with Cardiovascular Disease.

To assess the validity of the Ekblom-Bak cycle ergometer test in patients with cardiovascular disease admitted to cardiac rehabilitation. Estimated peak oxygen consumption from the Ekblom-Bak test was compared with directly measured peak oxygen consumption from a treadmill cardiopulmonary exercise test. Patients completed the cardiopulmonary exercise test first, followed by the Ekblom-Bak test after 24 h rest. Pearson's correlation coefficient (r) was used to establish the correlation between estimated and measured peak oxygen consumption, and Bland-Altman plots with limits of agreement were used to determine the bias between the 2 tests. Twenty-six patients were included in the final analysis. The Ekblom-Bak test significantly overestimated peak oxygen consumption. Agreement between estimated and measured peak oxygen consumption was: bias = 4.3 mL/kg/min (limits of agreement: -4.0-12.6 mL/kg/min). The Ekblom-Bak test overestimated peak oxygen consumption to such an extent that it cannot accurately assess cardiorespiratory fitness in patients with cardiovascular disease. Thus, the cardiopulmonary exercise test remains the test of choice.

Effect of Arm-Ergometry Versus Treadmill Supervised Exercise on Cardiorespiratory Fitness and Walking Distances in Patients With Peripheral Artery Disease: The ARMEX Randomized Clinical Trial.

To compare arm-ergometry and treadmill supervised exercise training on cardiorespiratory fitness and walking distances in patients with peripheral artery disease (PAD). ARMEX was a single-center, single-blinded, parallel group, non-inferiority trial enrolling symptomatic patients with PAD. Patients were randomized (1:1 ratio) to a 12-wk arm-ergometry (AEx) or standard treadmill (TEx) supervised exercise training protocol. The powered primary end point was the change in peak oxygen uptake (VO 2 ) at 12 wk, measured on a treadmill cardiopulmonary exercise test (CPX). Secondary outcomes included changes in VO 2 at the first ventilatory threshold (VT-1), ventilatory efficiency (ratio of minute ventilation [VE] to carbon dioxide production [VCO 2 ], VE/VCO 2 ), walking distances by CPX and 6-min walking test (6MWT), and self-reported walking limitations. Fifty-six patients (66±8yr; 88% male) were randomized (AEx, n =28; TEx, n =28). At 12 wk, VO 2peak change was not significantly different between groups (0.75 mL/kg/min; 95% CI, -0.94 to 2.44; P =.378), despite a significant increase only in AEx. VO 2 at VT-1 improved in both groups without between-group differences, and VE/VCO 2 slope improved more in AEx. The TEx attained greater improvements in walking distance by CPX (121.08 m; 95% CI, 24.49-217.66; P =.015) and 6MWT (25.08 m; 95% CI, 5.87-44.29; P =.012) and self-perceived walking distance. Arm-ergometry was noninferior to standard treadmill training for VO 2peak , and treadmill training was associated with greater improvements in walking distance. Our data support the use of treadmill as a first-line choice in patients with PAD to enhance walking capacity, but arm-ergometry could be an option in selected patients.

Abstract P345: Is a Fixed Value of the Rate of Gas Exchange Appropriate to Indicate the Maximum Effort of Obese and Nonobese Adults Undergoing a Treadmill Cardiopulmonary Exercise Test?

Introduction: Obese individuals present a higher O2 uptake/workload during a treadmill cardiopulmonary exercise test (CPET) in addition to chronotropic and biomechanical impairment, which preclude them, many times, from reaching a maximal rate of gas exchange (Rmax) &gt; 1.0. Therefore, it is necessary to develop reference values for Rmax for a treadmill CPET according to age, sex, and a wide range of body mass index (BMI). Objectives: To establish reference values for Rmax for a treadmill CPET according to age, sex, and BMI. Methods: We re-examined 1,612 treadmill ramp CPETs of adults (893 women), of which 772 were obese (BMI ≥ 30 kg/m 2 ). We excluded tests of nonobese participants with HRmax &lt; 85% of predicted, of any participant with a rate of perceived exertion in the BORG scale &lt; 4 (intense), and of those that we had operational problems during the test. We produced a Rmax percentile table according to sex, age (&lt; 33, 34 to 46, and &gt; 46 years), and BMI (&lt; 30 and ≥ 30 kg/m 2 ). We fit stepwise multiple regressions to investigate the influence of age, sex, BMI, and cardiovascular risk on Rmax. We also presented an obesity-specific equation to estimate maximum heart rate (HRmax). Results: We evaluated 442 eutrophic participants (BMI &lt; 25 kg/m 2 ), 398 were overweighted (BMI = 25 - 29.99 kg/m 2 ), 295 had class 1 obesity (BMI = 30 - 34.99 kg/m 2 ), 247 had class 2 obesity (BMI = 35 - 39.99 kg/m 2 ) and 230 had class 3 obesity (BMI ≥ 40 kg/m 2 ). Age, sex, and BMI were the main determinants of Rmax (R 2 = 0.195). The table with percentiles confirmed that the lower limits of Rmax did not reach 1.0, especially in older, obese, and female participants (Table 1). In the obese participants, we could predict HRmax as 195.2 - (0.796 x age). Conclusions: The Rmax values in a treadmill CPET should be chosen considering attributes such as age, sex, and BMI. Our results suggest that fixed values of Rmax are not appropriate to indicate maximum effort, especially in people with low cardiorespiratory fitness.

Step by Step: Evaluation of Cardiorespiratory Fitness in Healthy Children, Young Adults, and Patients with Congenital Heart Disease Using a Simple Standardized Stair Climbing Test.

(1) Background: Cardiorespiratory fitness (CRF) is known to be a prognostic factor regarding long-term morbidity and mortality. This study aimed to develop a standardized Stair Climbing Test (SCT) with a reliable correlation to spiroergometry and the 6MWT which can be used in healthy children as well as patients with congenital heart disease (CHD) and a restricted exercise capacity. (2) Methods: A total of 28 healthy participants aged 10-18 years were included. We tested the individuals' CRF by cardiopulmonary exercise testing (CPET) on a treadmill, the 6MWT, and a newly developed Stair Climbing Test (SCT). For the SCT, we defined a standardized SCT protocol with a total height of 13.14 m to achieve maximal exercise effects while recording time and vital parameters. To compare the SCT, the 6 Min Walking Test, and CPET, we introduced an SCT-Index that included patient data (weight, height) and time. To assess the SCT's feasibility for clinical practice, we also tested our protocol with five adolescents with complex congenital heart disease (i.e., Fontan circulation). (3) Results: A strong correlation was observed between SCT-Index and O2 pulse (r = 0.921; p < 0.001). In addition, when comparing the time achieved during SCT (tSCT) with VO2max (mL/min/kg) and VO2max (mL/min), strong correlations were found (r = -0.672; p < 0.001 and r = -0.764; p < 0.001). Finally, we determined a very strong correlation between SCT-Index and VO2max (mL/min) (r = 0.927; p = <0.001). When comparing the 6MWD to tSCT, there was a moderate correlation (r = -0.544; p = 0.003). It appears to be feasible in patients with Fontan circulation. (4) Conclusions: We were able to demonstrate that there is a significant correlation between our standardized SCT and treadmill CPET. Therefore, we can say that the SCT can be used as an easy supplement to CPET and in certain contexts, it can also be used as a screening tool when CPET is not available. The advantages would be that the SCT is a simple, quick, cost-effective, and reliable standardized (sub)maximal exercise test to evaluate CRF in healthy children on a routine basis. We can even assume that it can be used in patients with congenital heart disease.

Prediction of peak oxygen consumption using cardiorespiratory parameters from warmup and submaximal stage of treadmill cardiopulmonary exercise test.

This study investigates the quality of peak oxygen consumption (VO2peak) prediction based on cardiac and respiratory parameters calculated from warmup and submaximal stages of treadmill cardiopulmonary exercise test (CPET) using machine learning (ML) techniques and assesses the importance of respiratory parameters for the prediction outcome. The database consists of the following parameters: heart rate (HR), respiratory rate (RespRate), pulmonary ventilation (VE), oxygen consumption (VO2) and carbon dioxide production (VCO2) obtained from 369 treadmill CPETs. Combinations of features calculated based on the HR, VE and RespRate time-series from different stages of CPET were used to create 11 datasets for VO2peak prediction. Thirteen ML algorithms were employed, and model performances were evaluated using cross-validation with mean absolute percentage error (MAPE), R2 score, mean absolute error (MAE), and root mean squared error (RMSE) calculated after each iteration of the validation. The results demonstrated that incorporating respiratory-based features improves the prediction of VO2peak. The best results in terms of R2 score (0.47) and RMSE (5.78) were obtained for the dataset which included both cardiac- and respiratory-based features from CPET up to 85% of age-predicted HRmax, while the best results in terms of MAPE (10.5%) and MAE (4.63) were obtained for the dataset containing cardiorespiratory features from the last 30 seconds of warmup. The study showed the potential of using ML models based on cardiorespiratory features from submaximal tests for prediction of VO2peak and highlights the importance of the monitoring of respiratory signals, enabling to include respiratory parameters into the analysis. Presented approach offers a feasible alternative to direct VO2peak measurement, especially when specialized equipment is limited or unavailable.

Comparing the Physiological Responses to the 6-Minute Walk Test, Timed Up and Go Test, and Treadmill Cardiopulmonary Exercise Test.

Purpose: To compare physiological responses during a treadmill cardiopulmonary exercise test (CPX), 6-minute walk test (6MWT), and timed up and go test (TUGT) in individuals referred for unexplained breathlessness and symptom limited treadmill exercise testing. Methods: Heart rate (HR), oxygen consumption (V̇O2), carbon dioxide production (V̇CO2), respiratory exchange ratio (RER), minute ventilation (V̇E), systolic blood pressure (SBP), and rating of perceived exertion (RPE) were recorded throughout each test. Results: Each test demonstrated a significant increase (p < 0.01) in the cardiopulmonary (V̇O2, V̇CO2 and V̇E, RPE, SBP, and HR) and perceptual (RPE) responses from rest to end exercise. The increase in cardiopulmonary and perceptual responses was greatest for the CPX with significantly smaller responses demonstrated during the 6MWT (p < 0.01) and even smaller responses for the TUGT (p < 0.01 vs CPX and 6MWT). Conclusion: Not surprisingly, the treadmill CPX results is the greatest physiological response in our group. Despite being of short duration, the TUGT results in an increased physiological response.

Cardiorespiratory fitness is linked with heart rate variability during stress in "at-risk" adults.

Physiological mechanisms explaining why cardiorespiratory fitness (CRF) predicts cardiovascular morbidity and mortality are incompletely understood. We examined if CRF modifies vagally mediated heart rate variability (HRV) during acute physical or psychosocial stress or night-time sleep in adults with cardiovascular risk factors. Seventy-eight adults (age 56 years [IQR 50-60], 74% female, body mass index 28 kg/m2 [IQR 25-31]) with frequent cardiovascular risk factors participated in this cross-sectional study. They went through physical (treadmill cardiopulmonary exercise test [CPET]) and psychosocial (Trier Social Stress Test for Groups [TSST-G]) stress tests and night-time sleep monitoring (polysomnography). Heart rate (HR) and vagally mediated HRV (root mean square of successive differences between normal R-R intervals [RMSSD]) were recorded during the experiments and analyzed by taking account of potential confounders. CRF (peak O<inf>2</inf> uptake) averaged 99% (range 78-126) in relation to reference data. From pre-rest to moderate intensities during CPET and throughout TSST-G, HR did not differ between participants with CRF below median (CRF<inf>lower</inf>) and CRF equal to or above median (CRF<inf>higher</inf>), whereas CRF<inf>higher</inf> had higher HRV than CRF<inf>lower</inf>, and CRF correlated positively with HRV in all participants. Meanwhile, CRF had no independent associations with HR or HRV levels during slow-wave sleep, the presence of metabolic syndrome was not associated with recorded HR or HRV levels, and single factors predicted HRV responsiveness independently only to limited extents. CRF is positively associated with prevailing vagally mediated HRV at everyday levels of physical and psychosocial stress in adults with cardiovascular risk factors.

FATIGABILITY, FITNESS, AND CHRONO-NUTRITION: RESULTS FROM THE STUDY OF MUSCLE, MOBILITY AND AGING (SOMMA)

Abstract The Study of Muscle, Mobility and Aging (SOMMA) is a new longitudinal cohort study conducted at the University of Pittsburgh and Wake Forest University School of Medicine, coordinated by the San Francisco Coordinating Center, with management of biological specimens by the Translational Research Institute at AdventHealth. SOMMA aims to provide the foundation for discoveries in the biology of human aging, mobility and other age-related phenotypes. SOMMA enrolled 879 older women and men; mean age 76.3±5.0 years (range 70-94); mean walking speed 1.04±0.20 m/s; 59.2% women, and 15.8% identify as other than Non-Hispanic White. Our symposium will introduce novel baseline SOMMA findings on key measures related to fatigability, fitness, and chrono-nutrition. First, Dr. Schumacher will share results on the association between perceived physical and mental fatigability and cognitive function. Next, to begin to decipher how skeletal muscle energetics impact aging phenotypes, Ms. Gay will examine the relation between skeletal muscle energetics (ATPmax and maximal complex I&amp;II supported oxidative phosphorylation [maxOXPHOS]) and age-related physical fatigability. Our next two presentations will focus on cardiorespiratory fitness (VO2peak) measured by gold standard treadmill cardiopulmonary exercise testing (CPET), which declines with age. Ms. Moffit will explore whether a usual-paced 400m walk can predict VO2peak, and Dr. Erickson will examine the association between CPET measured VO2peak and circadian functions derived from rest-activity-rhythms extracted from wrist-worn accelerometers. Lastly, Dr. Farsijani will explore chrono-nutrition behaviors and their association with muscle health (i.e., D3-creatine, leg power). Discussant, Dr. Jennifer Schrack will provide insight to SOMMA’s novel work.

Effects of Handrail Support usage during CPET on Metabolic Responses in Healthy Participants

Background: Using the support of a handrail during cardiopulmonary exercise testing (CPET) may alter physiologic parameters. The purpose is investigate the effects of handrail usage during the CPET in the metabolic parameters outcomes of young adults. Material and Methods: 39 young adults (age in years, 20.8 ± 2.9) of both sexes, 17 woman and 22 men performed two treadmill CPET on Ellestad protocol, in non-consecutive days. The first (T1) offered access to the support of a handrail; after 7 days, the second (T2) was performed without it. Differences between protocols for metabolic variables were compared using paried the t-test and repeated measures ANOVAS with interaction. Results: Regardless of sex, all participants exhibited superior results of metabolic parameters at T2 in contrast to T1. During T2, there was a major perception of respiratory and muscular effort, as well as a higher respiratory quotient for both sexes. When comparing T1 with T2, the VE/VCO2 slope was also significantly higher for women (29.31 ± 4.7 and 27.27 ± 4.53). For both sexes, when comparing the tests by stages, it was observed in stages 2, 3 and 4 higher values in the metabolic parameters for T2. The percentile difference for both sexes was 17% higher in S3 for women (T1=26.20±4.1 ml.kg-1.min-1;T2 28.79±4.2 ml.kg-1.min-1) and men (T1= 40.07±6.6 ml.kg-1.min-1; T2 45.92±4.8 ml.kg-1.min-1).Conclusion: The holding of the handrail attenuated the participants' cardiorespiratory and metabolic responses by more than 15% during CPET. Material and Methods: 39 young adults (age in years, 20.8 ± 2.9) of both sexes, 17 woman and 22 men performed two treadmill CPET on Ellestad protocol, in non-consecutive days. The first (T1) offered access to the support of a handrail; after 7 days, the second (T2) was performed without it. Differences between protocols for metabolic variables were compared using paried the t-test and repeated measures ANOVAs with interaction. Results: Regardless of sex, all participants exhibited superior results of metabolic parameters at T2 in contrast to T1. During T2, there was a major perception of respiratory and muscular effort, as well as a higher respiratory quotient for both sexes. When comparing T1 with T2, the VE/VCO2 slope was also significantly higher for women (29.31 ± 4.7 and 27.27 ± 4.53). For both sexes, when comparing the tests by stages, it was observed in stages 2, 3 and 4 higher values in the metabolic parameters for T2. VO2 was approximately 17% higher at T2, stage 3, for women and men. Conclusion: The holding of the handrail attenuated the participants' cardiorespiratory and metabolic responses by more than 15% during CPET.

A Reference Equation for Peak Oxygen Uptake for Pediatric Patients Who Undergo Treadmill Cardiopulmonary Exercise Testing

Pediatric patients are often referred to cardiopulmonary exercise testing (CPET) laboratories for assessment of exercise-related symptoms. For clinicians to understand results in the context of performance relative to peers, adequate fitness-based prediction equations must be available. However, reference equations for prediction of peak oxygen uptake (VO2peak) in pediatrics are largely developed from field-based testing, and equations derived from CPET are primarily developed using adult data. Our objective was to develop a pediatric reference equation for VO2peak. Clinical CPET data from a validation cohort of 1,383 pediatric patients aged 6 to 18years who achieved a peak respiratory exchange ratio ≥1.00 were analyzed to identify clinical and exercise testing factors that contributed to the prediction of VO2peak from tests performed using the Bruce protocol. The resultant prediction equation was applied to a cross-validation cohort of 1,367 pediatric patients. Exercise duration, gender, weight, and age contributed to the prediction of VO2peak, generating the following prediction equation: (R2=0.645, p <0.001, standard error of the estimate=6.19ml/kg/min): VO2peak (ml/kg/min) =16.411+ 3.423 (exercise duration [minutes]) - 5.145 (gender [0=male, 1=female]) - 0.121 (weight [kg])+0.179 (age [years]). This equation was stable across the age range included in the present study, with differences ≤0.5ml/kg/min between mean measured and predicted VO2peak in all age groups. In conclusion, this study represents what we believe is the largest pediatric CPET-derived VO2peak prediction effort to date, and this VO2peak prediction equation provides clinicians who perform and interpret exercise tests in pediatric patients with a resource with which to better quantify fitness when CPET is not available.

Evaluation and application of treadmill Cardiopulmonary Exercise Testing and field measurement results of female national team water polo players

Abstract Introduction Due to intensive sport adaptation, examinations of elite athletes are a special entity of cardiology. Cardiovascular follow-up of elite athletes is a significant method of supporting safe and successful sport. In many sports like water polo, training work takes place in different environments and with different forms of movement, then the tests applied in laboratory circumstances. Although treadmill cardiopulmonary exercise testing (CPET) is widely used in cardiology screening, we have little information of its usefulness in physical fitness follow-up in non-running sports. Purpose We aimed to analyze and to compare the data of elite youth team (YT) and adult water polo players collected from maximal intensity cardio-pulmonary exercise testing (CPET) and field examinations in definition of current fitness status of the different age groups. Methods During the age- and sport specific field measurements (swimming tests) and CPET examinations, we collected resting and exercise heart rate data and lactate levels at defined time points. During CPET, continuous 12-lead ECG, gas analysis and repeated blood pressure measurements were also carried out. Results 46 female water polo players were examined (age: 18.5±5.9y, adults: 19, training: 18.0±7.9h/w). Comparing CPET and field measurements, no differences were found between resting heart rate (75.7±13.4vs73.1±13.0 BPM, p=0.22) and resting lactate levels (1.5±0.4vs1.6±0.6 mM, p=0.29). Achieved maximal heart rates were higher during CPET examinations, than during field tests (196.3±9.7 vs 191.0±12.5 BPM, p=0.001) On the contrary, maximal lactate levels were lower during CPET in comparison to field measurements (8.4±2.4 vs 9.6±2.7 mM, p=0.01). Lactate levels stayed high after routine cool-down swimming ordered by the trainers, but decreased after suggested further training (6.6±2.7 vs 3.7±1.6 mM, p=10-16). When comparing the age groups, CPET examinations showed similar relative maximal aerobic capacity (44.4±4.8vs44.9±5.5 ml/kg/min, p=0.72) and peak lactate values (8.2±2.7vs8.7±1.9 mM, p=0.48), while maximal heart rates were higher in YT groups (200.7±7.2 vs 190.1±9.6 BPM, p&amp;lt;0.001) as compared to adults. Similarly, maximal lactate levels showed no differences (9.1±2.6 vs 10.4±2,7 mM, p=0.13), while maximal heart rates were higher in YT groups (197.7±10.0 vs 181.4±8.9 BPM, p&amp;lt;0.001) as compared to adults during field examinations. Conclusions Although field measurements and laboratory CPET results differ from several points of view, differences between age groups and the kinetics of the data are similar. Maximal heart rates are easier to achieve during CPET, while more intensive lactate increase could be observed during field measurements. Combining the above examinations helps defining maximal physiological values, fitness status, differences between different age groups, and optimizing training plans, as well as differentiating between physiological and pathological sport adaptation.

Abstract 14771: Chronotropic Incompetence and Response to Exercise Training by HIV Status in the Exercise for Healthy Aging Study

Background: People with HIV (PWH) have lower exercise capacity compared to HIV-uninfected peers. Chronotropic incompetence (CI), the inability to increase heart rate during exercise, may contribute to reduced exercise capacity. We hypothesized that PWH would have lower adjusted heart rate reserve (AHRR=(HR peak -HR rest )/(220-Age-HR rest ), a measure of chronotropy, normal &gt;80%) and that AHRR would improve with exercise training. Methods: The Exercise for Healthy Aging Study included sedentary adults ages 50-75 with (PWH) and without HIV (controls) recruited for a 24-week exercise training program. Participants exercised at moderate intensity for weeks 1-12 and were then randomized to continue moderate or advance to a higher intensity of exercise for weeks 13-24. We compared prevalent CI on treadmill cardiopulmonary exercise testing by HIV. We compared AHRR and change in AHRR from baseline to 12 and 24 weeks by HIV status using mixed effects models. Finally we explored whether improved chronotropy could explain the greater benefit of exercise observed among PWH. Results: Among 32 PWH and 37 controls (median age 56, 7% female, mean BMI 28 mg/m 2 ), 9/31 (29%) with HIV compared to 4/38 (11%) controls had CI (p=0.07). At entry, AHRR was lower among PWH (91 vs 102%; difference 11%, 95%CI 2.5-19.7; p=0.01). At week 12, AHRR normalized among 27 PWH (+8%, 95%CI 4-11; p&lt;0.001) and sustained at week 24 (+5, 95%CI 1-9; p=0.008) compared to no change among 31 controls (95%CI -4 to 4; p=0.95; p interaction =0.004). Accounting for AHRR, the greater benefit of exercise observed among PWH at 12 weeks (peak VO 2 +1.5 ml/kg/min more than controls, 95%CI 0.1 to 2.9, p=0.04) was attenuated (0.4 ml/kg/min independent of AHRR, 95%CI -0.9 to 1.8; p=0.53). After 24 weeks of exercise, only 4/26 (15%) PWH met the definition for CI compared to 3/29 (10%) of controls (p=0.70). Conclusions: Chronotropic incompetence may contribute to reduced exercise capacity among PWH and improve with exercise training.

Abstract 14659: Muscle Oxygenation Responses to Acute Exercise and Cellular Biomarkers of Vascular Health in Veterans With Chronic Kidney Disease

Introduction: Increased susceptibility of endothelial dysfunction and skeletal muscle impairments suggest peripheral limitations as an explanation for diminished aerobic capacity in chronic kidney disease (CKD) patients. However, data on peripheral limitations in CKD patients is limited. Hypothesis: We hypothesized CKD patients would experience reduced muscle oxygenation responses to acute exercise and cellular evidence of declines in vascular health compared to those without CKD. Methods: Sixteen male Veterans (CKD: n=9, age 74±6 yrs, eGFR, 41.7±10 mL/min/1.73 m 2 ; non-CKD controls (CON): n=7, age, 67±8 yrs, eGFR, 75±10.6 mL/min/1.73 m 2 ) completed treadmill cardiopulmonary exercise testing via the Modified Bruce protocol. Oxygenation responses were obtained from the medial gastrocnemius using near-infrared spectroscopy. Blood samples were collected at rest and analyzed for colony-forming units (CFU), flow-cytometry of mononuclear cells (MNCs) focusing on endothelial lineage cells and gene expression of MNCs. Effect sizes between groups were determined using Hedge’s g (g). Results: At peak exercise, oxygen consumption (VO 2peak 19±5 vs 25.8±5.2 ml/kg/min -1 , g=1.2), heart rate (HR peak 132±21 vs 160±9 bpm, g=1.6), oxygen extraction (Δ[HHb] 14.8±10.8 vs 24.9±6.8 a.u., g=1.0), and change in total hemoglobin concentration (Δ[tHb] 8.9±5.1 vs 22.5±12.8 a.u., g=1.4) were lower in CKD compared to CON. At an exercise intensity of 3.4 METs, Δ[HHb] and Δ[tHb] were 42% and 54% lower (8.0±7.8 vs 13.8±8.8 a.u., g=0.6 and 4.9±4.1 vs 10.7±4.5 a.u., g=1.2) in CKD vs CON, despite no differences in oxygen consumption or heart rate. CD34 + 184 expression was 47% lower in CKD vs CON (0.2±0.04 vs 0.38±0.48 %, g=0.5). CFU was significantly inversely correlated with body mass index and waist circumference (r=-0.67, p=0.034; r=-0.65, p=0.041). Conclusions: Preliminary data from this ongoing study suggest oxygen extraction and capillary blood volume expansion are impaired during exercise in CKD patients when compared to those without CKD. CD34 + 184 expression was lower in CKD patients versus those without CKD, indicating poor hematopoietic stem cell migratory function in the CKD group. In addition, an inverse association between CFU and body habitus was observed.

Short intermittent taekwondo test to assess athlete's physiological and metabolic profile.

The aim of this study was to assess the effectiveness of a new Short Intermittent Taekwondo Test (SITT) in 17 black belt athletes. Maximal oxygen uptake (V̇O<inf>2max</inf>), carbon dioxide production (V̇CO<inf>2</inf>), respiratory exchange ratio (RER), heart rate (HR), and blood lactate concentration [La]+ during treadmill cardiopulmonary exercise test (CPET) and SITT were compared. SITT started with 10 sec of all-out kicks, alternating legs, and progressively increasing 5 s on each stage until the 4th stage. After the 4th stage the participants performed 25 s of turning kicks (Dolleo chagi), on each stage until the last (10th stage). The passive recovery phase after the 4th and the 7th stage lasted 30 s. V̇O<inf>2max</inf> and maximal HR<inf>max</inf> were not significantly different (P=0.85 vs. P=0.76) between tests, while RER and [La]+ were significantly higher in SITT than in CPET (P=0.002 vs. P=0.001). No difference in RPE (P=0.84) was found. A significant positive correlation between two tests for V̇O<inf>2max</inf> and HR<inf>max</inf> was found. Our findings showed that SITT induces physiological responses like CPET suggesting that it can be used to assess aerobic power in national taekwondo athletes, thus helping coaches to select correctly training intensities and monitor athletes' aerobic performance along the training phases.

Effect of bariatric surgery on cardio-psycho-metabolic outcomes in severe obesity: A randomized controlled trial.

Randomized evidence comparing the cardiovascular effects of surgical and conservative weight management is lacking. In this single-center, open-label randomized trial, obese patients with indication for Roux-en-Y gastric bypass (RYGB) and able to perform treadmill cardiopulmonary exercise testing (CPET) were included. After a 6-12 month run-in phase of multimodal anti-obesity treatment, patients were randomized to RYGB or psychotherapy-enhanced lifestyle intervention (PELI) and co-primary endpoints were assessed 12 months later. Thereafter, PELI patients could opt for surgery and patients were reassessed 24 months after randomization. Co-primary endpoints were mean change (95 % confidence intervals) in peak VO2 (ml/min/kg body weight) in CPET and the physical functioning scale (PFS) of the Short Form health survey (SF-36). Of 93 patients entering the study, 60 were randomized. Among these (median age 38 years; 88 % women; mean BMI 48·2 kg/m2), 46 (RYGB: 22 and PELI: 24) were evaluated after 12 months. Total weight loss was 34·3 % after RYGB vs. 1·2 % with PELI, while peak VO2 increased by +4·3 ml/min/kg (2·7, 5·9) vs +1·1 ml/min/kg (-0·2, 2·3); p < 0·0001. Respective improvement in PFS score was +40 (30, 49) vs +10 (1, 15); p < 0·0001. 6-minute walking distance also favored the RYGB group: +44 m (17, 72) vs +6 m (-14, 26); p < 0·0001. Left ventricular mass decreased after RYGB, but not with PELI: -32 g (-46, -17) vs 0 g (-13,13); p < 0·0001. In the non-randomized follow-up, 34 patients were assessed. Favorable changes were sustained in the RYGB group and were repeated in the 15 evaluated patients that opted for surgery after PELI. Among adults with severe obesity, RYGB in comparison to PELI resulted in improved cardiopulmonary capacity and quality of life. The observed effect sizes suggest that these changes are clinically relevant.

Physical fitness, hormonal profile, nutritional and psychological aspects assessment of transgender women volleyball players submitted to physical tests: protocol paper of a prospective cohort

To evaluate aerobic capacity, strength and other physiological, nutritional, and psychological variables which may influence the performance of transgender women (TW) athletes and compare them to cisgender women (CW) and...

Exercise intensity domains determined by heart rate at the ventilatory thresholds in patients with cardiovascular disease: new insights and comparisons to cardiovascular rehabilitation prescription recommendations

ObjectivesTo compare the elicited exercise responses at ventilatory thresholds (VTs: VT1 and VT2) identified by cardiopulmonary exercise testing (CPET) in patients with cardiovascular disease (CVD) with the guideline-directed exercise intensity...