Predicted VO2 Max Research Articles

Acute effects of bolus water intake on post-exercise orthostatic hypotension and cardiovascular hemodynamics.

Water intake is known to be effective in preventing orthostatic hypotension (OH). However, it is unknown whether water intake would be effective in acutely preventing exercise-induced OH. Fourteen adults (men/women: 7/7, age: 20 ± 8years) were recruited. Each subject underwent two protocols with and without 500ml water intake using a randomized crossover design (Water vs. Control). Participants underwent 30min of cycle ergometry at the 60-70% predicted VO2 max. OH and hemodynamics were assessed before and after exercise, and immediately (Water 1) and 20min (Water 2) after the water intake. OH was evaluated with a 1-min standing test as the criteria for systolic blood pressure (SBP) < 90mmHg. A cross-spectral analysis for RR and SBP variability was used to evaluate the cardiac autonomic activity and baroreflex sensitivity. In both protocols, the incidence of OH increased after the exercise. The incidence of OH was lower in Water than in Control at Water 1 (OR: 0.093, 95% CI: 0.015-0.591). Heart rate was lower and SBP was higher in Water than in Control at Water 1 and 2 (P < 0.05). High-frequency power of RR variability and transfer function gains in Water were normalized and higher than in Control at Water 1 and 2 (P < 0.05). The ratio of low- to high-frequency power of RR variability in Water was normalized and lower in Water than in Control at Water 1 (P < 0.05). Our findings indicate that water intake may prevent acute exercise-induced OH, accompanied by normalized cardiac autonomic activity and baroreflex sensitivity.

Respiratory Muscle Strength as a Predictor of VO2max and Aerobic Endurance in Competitive Athletes

This study explores the association of respiratory muscle strength with aerobic endurance kinetics among athletes, with a specific focus on maximal oxygen consumption (VO2max). Previous research has elucidated the complex interactions between respiratory and skeletal muscles during exercise, highlighting the critical role of efficient respiration in maximizing athletic performance. The interplay between active skeletal muscles and respiratory muscles, especially the influence of respiratory muscle fatigue on exercise capacity, is well-documented. High-intensity exercise has been shown to activate the respiratory muscle metaboreflex, which can restrict blood flow to working muscles, thereby impacting the energy required for respiration. A total of 41 athletes, drawn from the disciplines of biathlon, judo, and cross-country, participated in this study. Respiratory function tests (RFTs) were administered to assess various respiratory parameters, including changes in chest circumference. Additionally, maximal oxygen consumption (VO2max) and heart rate were measured during a treadmill test. To explore the associations between VO2max and ventilatory parameters—namely, ventilation (VE), oxygen consumption (VO2), carbon dioxide production (VCO2)—as well as respiratory metrics, linear regression analysis was employed. Based on the standardized regression coefficients (β), it was found that maximum expiratory pressure (MEP) (mean ± SD: 130.95 ± 42.82) and inspiratory diaphragmatic circumference values were significantly associated with VE, VO2, and VCO2. Conversely, the other predictor variables did not exhibit a significant effect on VE (mean ± SD: 134.80 ± 36.69), VO2 (mean ± SD: 3877.52 ± 868.47 mL), and VCO2 (mean ± SD: 4301.27 ± 1001.07 mL). Similarly, measurements of chest circumference (mean ± SD: 91.40 ± 10.72 cm), MEP, and diaphragmatic circumference during inspiration (mean ± SD: 95.20 ± 10.21 cm) were significantly associated with VO2max (mean ± SD: 58.52 ± 10.74 mL/kg/min), while the remaining predictor variables did not demonstrate a significant effect on VO2max. Additionally, a multiple linear regression analysis was conducted to examine the combined effects of respiratory muscle strength and ventilatory factors on VO2max. The model, which included interaction terms, explained 89.9% of the variance in VO2max (R2 = 0.899, adjusted R2 = 0.859). Significant interactions were found between MIP and VE (B = −0.084, p = 0.006), as well as MEP and VE (B = 0.072, p = 0.012). These findings suggest that respiratory muscle strength plays a more substantial role in determining VO2max in individuals with higher ventilatory efficiency, highlighting the importance of both respiratory strength and breathing efficiency in aerobic performance. Our findings underscore the importance of considering respiratory muscle strength in assessing and enhancing athletes’ aerobic performance. Integrating objective measurements such as maximal inspiratory and expiratory pressure assessments into routine performance evaluations allows coaches and sports scientists to monitor changes in respiratory function over time and adjust training protocols accordingly.

Prediction of the maximum oxygen consumption (VO2max) for young Saudi females using exercise parameters

BACKGROUND: Maximum oxygen consumption (VO2max), an essential indicator of integrated function of the cardiovascular, respiratory, and muscular systems, is an excellent predictor of all-cause morbidity and mortality. Direct measurement is a sophisticated procedure which for some individuals is difficult to perform. The use of international formulae leads to overestimation or underestimation of values. Therefore, the present study aimed to generate a best-fit VO2max prediction formula for young Saudi females. MATERIALS AND METHODS: One hundred and two randomly selected young healthy Saudi females (19–25 years) with normal body mass index (18.5–24.99 kg m−2) and sedentary lifestyle underwent maximum cardiopulmonary exercise testing on cycle ergometer when using breath-by-breath analyzing system. Hemodynamic and ventilatory parameters were assessed before and during the maximum exercise. Significantly correlated exercise and nonexercise parameters enterd in multiple linear regression analysis to find the best-fit model, and used to generate a VO2max prediction formula. RESULTS: The mean measured VO2max was 1449.1 ± 233.92 ml min−1. The VO2max prediction formula was 1304.193 ± 17.902 × body weight + 43.857 × time until exhaustion − 6.83 × maximum heart rate. The mean calculated VO2max was 1449.14 ± 143.97 ml min−1. No statistically significant difference was observed between the measured and calculated VO2max. The Bland–Altman test for the limit of agreement was performed and showed good agreement between the two values with a minute proportional bias. The standard error of the estimate was 156.34, which is approximately 10.6% of the mean measured VO2max. Reliability analysis yielded a Cronbach’s alpha of 0.709. CONCLUSION: This study presents a reliable and valid VO2max prediction formula for young Saudi females. This nationally generated formula is far more representative of the VO2max value than international formulae. We recommend the implementation of this formula and an investigation of its validity in other Saudi population groups.

Confirmatory Study on Prediction of Maximal Oxygen Uptake by Ensemble Learning Algorithm

Objective: The prediction model of maximal oxygen uptake (VO2max) was established by different ensemble learning methods. Compared with multiple linear regression, a common prediction method of VO2max, the effectiveness of the ensemble learning model is verified, and screen out the optimal VO2max prediction model. Methods: A total of 84 male college students, were recruited, informed of the purpose and procedure of the experiment, and passed the PAR-Q questionnaire screening. Cardiopulmonary Exercise Test (CPET), lung function, body composition test, VO2max, minute ventilation volume (VE), tidal volume (Vt), weight, and other related indicators. After the correlation analysis of the experimental results, a VO2max multiple linear regression model and an ensemble learning prediction model are computed. Results: The indicators that finally enter the multiple linear regression equation include: weight, Vt, VE. The regression equation is: VO2max (ml/kg/min) = 52.455+0.005×VT (ml/min) + 0.111×VE (L/min)-0.441×weight (kg), and the regression coefficient test results is extremely significant (P&lt;0.01). The VO2max prediction model is computed by using the ensemble learning algorithm and among the five prediction models, it is found that Weighted average (R^2=0.7715) has the best effect, and higher than multiple regression model, there is no significant difference between the actual value and the predicted value VO2max (P&gt;0.05). Conclusion: In the case of a small sample size, the weighted average model predicts VO2max the most accurately, compared with multiple regression models, the ensemble learning model can include more basic indicators, the evaluation of VO2max in the body is more comprehensive, and the prediction results are more accurate.

Comparison of community ambulation intensity determined from overground and treadmill walking cadence cut points: Is there a relationship between step activity measures and predicted VO2 max in healthy children and adults?

BackgroundThis study was designed to evaluate the effect of using maximal cadence criteria cut points established during overground and treadmill walking, on intensity outputs measured during community ambulation. The second aim was to establish the relationship between cardiovascular fitness (predicted VO2 max capacity) and community ambulation intensity performance, in typically developing individuals. Research QuestionWhat is the effect on intensity measures when using cadence cut point criteria derived from overground and treadmill walking and does predicted VO2 max correlate with exercise related community activity in a typically developing population? MethodsA group of 37 typically developing participants between 8 and 27 years of age, underwent a graded submaximal VO2 testing protocol followed by a typical week of community ambulation, recorded with a step activity monitor. Maximum cadence criteria established during overground and treadmill walking were applied and the data were compared. The weekly step activity variables included: total steps, total ambulatory time, intensity, duration, and volume. Predicted VO2 Max was calculated, and correlations calculated to step activity outputs. ResultsResults showed significant differences (p<0.001) between cadence cut point criteria across all intensity measures except in the amount of time spent in the 30–60 % intensity category (p=0.182). Predicted VO2 max did not significantly correlate with step activity outputs related to exercise (moderate+ intensity and long duration ambulatory bouts; p>0.277). SignificanceThis study illustrates the importance of close consideration in applying recommended cut off criteria when assessing intensity outputs from step activity data. Cadence from both overground and treadmill walking were collected in a controlled lab setting, but the influence of the treadmill mechanical and forced cadence criteria must be considered when selecting intensity cut points.

Comparison of time-matched aerobic, resistance or combined exercise training in women living with obesity: The EXOFFIT study.

Improvements in cardiorespiratory fitness (CRF) have been shown to largely attenuate the negative health risks associated with obesity. To date, literature on women with obesity has focused upon the evaluation of aerobic-based exercise interventions. Hence, there is a need to evaluate resistance and combined interventions with this cohort. This study aimed to evaluate the feasibility and efficacy of three exercise modalities in women with obesity for improving CRF, strength, body composition and other health outcomes. Sixty-seven women with obesity were randomly assigned to the control (CON) or one of three exercise groups (aerobic [AE], resistance [RE], COM). Exercise groups were trained x3 times/week for 12weeks (up to 150-min/week). Feasibility outcomes included adherence, attendance, recruitment and retention rates and adverse events. Secondary outcomes were CRF (predicted VO2 max), body composition (body weight [BW], waist circumference [WC], body fat percentage [%BF], fat mass [FM] and lean mass) and strength (5RM bench press, leg dynamometry, grip strength) and self-reported measures of physical activity, mood, sleep, pain and quality of life. Findings support the feasibility of all three exercise modalities in terms of adherence, attendance, and retention. Interventions with a resistance component (COM and RE) were associated with the greatest improvements across the broad range of health outcomes measured. Combined was the most promising for body composition outcomes including body mass index (Effect size [ES]=0.79, p=0.04), BW (ES=0.75, p=0.05), %BF (ES=0.77, p=0.04), FM (ES=0.83, p=0.03) and WC (ES=0.90, p=0.02), physical activity (i.e., moderate physical activity [ES=0.69, p=0.07), mood (ES=0.83, p=0.03) and sleep (ES=0.78, p=0.04). Resistance was most promising for CRF (ES=1.47, p=0.002), strength (i.e., bench press [ES=2.88, p=<0.001]) and pain (i.e., pain severity [ES=0.40, p=0.31]). For health outcomes, these results indicate the importance of including a resistance component when prescribing exercise for women with obesity to achieve meaningful improvements. ISRCTN13517067.

Associations between Multiple Health Indicators and Carotid Artery Intima-Media Thickness in A Healthy and Active Elderly Population.

The purpose of this study was to examine correlations between health indicators (age, BMI, blood pressure (BP), functional strength (FS), handgrip strength, and predicted VO2 max) and carotid intima-media thickness (cIMT) in an active 50 years+ population. Study participants' mean cIMT was also compared to the cIMT mean of the general population. Health screenings were conducted on 1818 participants at the Huntsman World Senior Games from 2016 to 2019. Pearson's correlations, Spearman's correlations, and ANOVA were performed using SPSS. Weak but significant correlations were evident between cIMT and age (r = 0.283, p < 0.001), systolic BP (r = 0.253, p = 0.001), diastolic BP (r = 0.074, p = 0.016), weight (r = 0.170, p < 0.001), height (r = 0.153, p < 0.001), handgrip L (r = 0.132, p < 0.001), handgrip R (r = 0.074, p < 0.029), and BMI (r = 0.07, p = 0.029); non-significant correlations were evident with predicted VO2 max (r = -0.035, p = 0.382), and FS (r = -0.025, p = 0.597). When controlling for age, systolic BP, and sex, only handgrip L (r = 0.225, p = 0.014) was significantly correlated with cIMT. Mean cIMT for this cohort was lower across all sexes and age-matched groups (cIMT = 0.6967 mm (±0.129)). Physical activity is linked to reduced cIMT. Most health-related indicators in this study were significantly but weakly correlated with cIMT. Additional research is needed before common indicators can be used as a surrogate for cIMT and CVD risk. Results from this study can provide clinicians with additional information to reduce CVD risk through modifiable risk factors. Classic CVD risk factors such as systolic BP and BMI should be considered in patients regardless of lifestyle.

Effects of combined dietary intervention and physical-cognitive exercise on cognitive function and cardiometabolic health of postmenopausal women with obesity: a randomized controlled trial

BackgroundPostmenopausal women with obesity are markedly at risk of cognitive impairment and several health issues. Emerging evidence demonstrated that both diet and exercise, particularly physical-cognitive exercise are involved in cognitive and health benefits. However, the comparative effect of diet, exercise, and combined interventions in postmenopausal women with obesity on cognition and cardiometabolic health is still lacking. Identifying the effective health promotion program and understanding changes in cardiometabolic health linking these interventions to cognition would have important medical implications. This RCT aimed to examine the effect of single and combined interventions of diet and exercise on cognitive function and cardiometabolic health in postmenopausal women with obesity.MethodsNinety-two postmenopausal women with obesity were randomly assigned to diet group (intermittent fasting 2 days/week, 3 months), exercise group (physical-cognitive exercise 3 days/week, 3 months), combined group, or control group (n = 23/group). All cognitive outcomes and cardiometabolic outcomes were measured at baseline and post-3 months. Primary outcomes were executive functions, memory, and plasma BDNF levels. Secondary outcomes were global cognition, attention, language domain, plasma adiponectin levels, IL-6 levels, metabolic parameters, and physical function.ResultsAt the end of the 3-month intervention, the exercise and combined group demonstrated significant memory improvement which was accompanied by significant improvements in plasma BDNF level, insulin levels, HOMA-IR, %body fat, and muscle strength when compared to controls (p < 0.05). Only the combined intervention group demonstrated a significant improvement in executive function and increased plasma adiponectin levels when compared to control (p < 0.05). Surprisingly, no cognitive improvement was observed in the diet group (p > 0.05). Significant reduction in cholesterol levels was shown in the diet and combined groups when compared to controls (p < 0.05). Among the three intervention groups, there were no significant differences in all cognitive outcomes and cardiometabolic outcomes (p > 0.05). However, all three intervention groups showed significant improvements in plasma BDNF levels, weight, BMI, WHR, fat mass, and predicted VO2 max, when compared to control (p < 0.05).ConclusionThese findings suggest that combined physical-cognitive exercise and dietary intervention are promising interventions to improve cognition and obesity-related complications of postmenopausal women with obesity.Trial registrationNCT04768725 (https://clinicaltrials.gov) 24th February 2021.

StepTest4all: Improving the Prediction of Cardiovascular Capacity Assessment in Young Adults.

Cardiovascular capacity, expressed as maximal oxygen uptake (VO2max), is a strong predictor of health and fitness and is considered a key measure of physiological function in the healthy adult population. The aim of this study was to investigate the influence of the physical activity levels (PAlevel) of participants in the StepTest4all (validated protocol for the estimation of VO2max in adults). The sample consisted of 69 participants, including 27 women (age 21.7 ± 3.6 years; body mass = 63.5 ± 14.8 kg; height = 1.64 ± 0.06 m; body mass index = 23.7 ± 5.3 kg/m2) and 42 men (aged 21.7 ± 3.4 years; body mass = 72.0 ± 7.3 kg; height = 1.77 ± 0.07 m; body mass index = 23.1 ± 2.1 kg/m2). The participants were assigned to one of the two groups: (i) the VO2max prediction group and (ii) the prediction model validation group. In the multiple linear regression, the following predictors of VO2max remained significant: sex (p < 0.001), physical activity level (p = 0.014), and HRR60 (p = 0.020). The prediction equation (R2 = 74.0%, SEE = 4.78) showed a close and strong relationship between the measurements and can be expressed as follows: VO2max = 17.105 + 0.260·(HRR60) + 8.563·(sex) + 4.097·(PAlevel), in which HRR60 is the magnitude of the HR decrease (bpm) in one minute immediately after stopping the step, and sex: men = 1, women = 0, and PAlevel is level 1 (low), level 2 (moderate), and level 3 (high). The StepTest4all was shown to be a suitable method for estimating cardiovascular capacity, expressed as VO2max, in young adults. Retaining PAlevel as a significant predictor allows us to better individualize the participants' VO2max.

Identifying the optimal workload combination for maximizing oxygen consumption estimation in submaximal tests

For decades, indirect submaximal tests using heart rate (HR) to estimate maximal oxygen consumption (VO2max) have been used for assessing cardiorespiratory fitness without pushing individuals to their limits. However, the optimal combination of submaximal workloads to use for maximizing estimation performance remains unclear. The study reprocessed data from 18 adolescent athletes undergoing a cycle ergometer incremental test with step-wise increments of 15 Watt/min until volitional exhaustion, sourced from a publicly available dataset. Multiple HR-derived metrics were computed over six distinct combinations of increasing workloads (50, 65, 80, 95, 110, 125 Watt). Principal component analysis was employed for dimensionality reduction. The top-performing regression model was chosen after training and validating various regression models, including machine learning-based ones. The HR data recorded at a single workload of 50 Watt was already adequate for estimating group VO2max, exhibiting similar scores (p = 0.80) to actual group values. Utilizing three consecutive workloads (50, 65, and 80 Watt) provided the most accurate individual VO2max prediction, revealing the highest correlation coefficient (0.71) along with the smallest bias (0.019 L/O2) and standard deviation (0.39 L/O2) across all six combinations. The project identifies optimal workloads for constructing new submaximal VO2max estimation tests. Additionally, it introduces new models for estimating VO2max for adolescents, each with varying performance based on the number of workloads utilized.

Comparison of VO2max Estimations for Maximal and Submaximal Exercise Tests in Apparently Healthy Adults.

Due to limited accessibility, direct measurement of VO2max is rarely performed in clinical settings or sports centers. As a result, regression equations have been developed and are currently used during exercise tests to provide an indirect estimation. The American College of Sports Medicine (ACSM) has recommended a regression equation for running to provide an indirect estimation of VO2. However, significant differences have been observed between these estimations and directly measured VO2max. Additionally, since submaximal assessments may be more convenient for both athletes and sedentary/diseased individuals, they were included in the analysis. This study aimed to evaluate the accuracy of VO2max estimations provided using the ACSM running equation when used during both maximal and submaximal exercise tests among adult runners. A total of 99 apparently healthy and active adults (age: 39.9 ± 12.2 years; VO2max: 47.4 ± 6.0 mL O2/kg∙min-1) participated in this study. Two types of submaximal estimations were performed to predict VO2max: one based on age-predicted maximal heart rate (HRmax) (ACSMsubmax,Fox), and the second using the actual HRmax measured during the exercise test (ACSMsubmax,measured). The measured VO2max was compared to these estimations obtained from a single exercise test. Both maximal and submaximal exercise tests significantly overestimated VO2max (ACSMmax: +9.8, p < 0.001; ACSMsubmax,Fox: +3.4, p < 0.001; ACSMsubmax,measured: +3.8 mL O2/kg∙min-1, p < 0.001). However, the submaximal estimations were closer to the measured VO2max (p < 0.001). This analysis demonstrated that the included methods overestimated the true VO2max. Nonetheless, the submaximal exercise tests provided a more accurate prediction of VO2max compared to the maximal exercise tests when using the ACSM running equation.

Association between maximal oxygen consumption and physical performance tests among older adults with cognitive frailty

IntroductionCardiorespiratory fitness has an inverse relationship with cognitive impairment and frailty in older adults. Direct assessment of maximal oxygen consumption (VO2 max) is the gold standard to assess cardiorespiratory fitness. However, it is costly and requires a laboratory setting. Therefore, VO2 max estimation among older adults with cognitive frailty (CF) will allow the assessment of aerobic capacity, which is commonly overlooked due to the complexity of the test. AimThis study aims to determine the use of one of three physical performance tests (2-minute step, 2-minute walk, and 1-minute sit to stand) to effectively estimate cardiorespiratory fitness among older adults with CF. MethodsIn this cross-sectional study, community-dwelling individuals aged 60 years old and above in Klang Valley were screened for CF. The participants performed three physical performance tests (2-minute walk, 2-minute step, and 1-minute sit to stand) followed by treadmill-based maximal exercise testing on another day. ResultsA total of 32 older adults with cognitive frailty (mean age; SD: 67.1;4.7 years) participated in this study. Nearly half of them had hypertension (43.5 %), hypercholesterolemia (43.5 %), and multimorbidity (47.8 %). Among the endurance tests performed, only the 2-minute walk test independently predicted VO2 max by sex-specific with men (R2 = 0.58, p = 0.03) and women (R2 = 0.34, p = 0.01). The 2-minute walk test had good agreement with VO2 max (ICC = 0.77, 95 % CI: −3.1–2.4). ConclusionThe 2-minute walk test is a valid tool for estimating cardiorespiratory fitness among older adults with CF. However, it should be further tested across a larger population.

Prediction of maximal oxygen uptake based on anthropometric indices in Iranian male adults.

Assessment of maximal oxygen consumption is important in both general community and occupational settings. Validity and reliability tests are needed to indicate the functionality of the cardiopulmonary system. This study aimed to establish a maximal oxygen consumption (VO2max) prediction model using anthropometric and demographic variables for young adults in Iran. This cross-sectional study was conducted on 64 healthy young men aged 19-29 years. Oxygen consumption was measured directly and the prediction models to estimate VO2max were determined by multiple linear regression. The accuracy of the prediction models was considered using regression coefficient (R), coefficient of determination (R2), and standard error of estimate (SEE). The average VO2max was 44.02±4.31 ml/kg/min. Significant correlations were found between the measured VO2max and the anthropometric and demographic variables (r = 0.16-0.86, P < 0.05). Three significant regression models with acceptable accuracy were developed (R2 = 0.67-0.71, SEE = 3.19-3.21). The predictive models consisted of 3-5 variables as significant predictors of VO2max and had acceptable accuracy for Iranian young adults. The proposed models are a simple and valid tool that can be used to estimate the VO2max in the field and in laboratory settings.

Determinants of NT-proBNP Levels in patients with a systemic right ventricle: a new cut-off level for risk stratification?

Abstract Introduction The role of N-terminal natriuretic peptide (NT-proBNP) in the risk prediction of patients with a systemic left ventricle is indisputable. However, its value in patients with a systemic right ventricle (sRV) is not well defined. Method Ninety-eight patients with NT-proBNP values at baseline from the randomized clinical trial SERVE were included. The correlation between baseline NT-proBNP values and parameters of bi-ventricular volumes and function quantified by cardiac magnetic resonance was assessed by means of adjusted linear regression models. The prognostic value of NT-proBNP and other established prognostic markers were assessed by means of adjusted cox proportional hazards model, survival analysis and c-statistic. The primary outcome was defined as the occurrence of either clinically relevant arrhythmia, heart failure or death. Results Median age [interquartile range, IQR] at baseline was 39 years [32,48] and 32% were female. Median NT-proBNP was 238 [137,429] ng/L. Coefficients of determination for the relationship between NT-proBNP levels and right ventricular end-systolic and end-diastolic volume index, and ejection fraction (RVEF) were +0.481, p&amp;lt;0.001; +0.427, p&amp;lt;0.001; and -0.561, p&amp;lt;0.001, respectively. The sex and age adjusted hazard ratio [95% confidence interval, CI] for NT-proBNP values above the 75th percentile (429ng/L) showed an exponential increase (Figure) and there was a significant difference in survival comparing the group above our cut-off value and the group below it (Table). After adjusting for age and sex, the prognostic value of NT-proBNP was comparable to the prognostic value of RVEF and predicted VO2 max (C-statistic: 0.71, 0.72 and 0.71, respectively). Conclusion NT-proBNP levels correlated significantly with right ventricular parameters assessed by means of CMR. Measurement of NT-proBNP is a reliable and convenient tool for the prediction of adverse outcomes in patients with a sRV and using the cut-off value of 429ng/L could assist in the risk stratification for this population.

Fragmented QRS complexes in veteran athletes

Abstract Background QRS fragmentation (fQRS), characterized by multiple peaks within the QRS, is considered an adverse risk marker that may indicate underlying myocardial fibrosis and has been implicated in cardiomyopathies. The presence of fQRS is often noted in pre-participation screening of athletes. In this study, we aimed to investigate the prevalence and clinical significance of fQRS in a cohort of ostensibly fit veteran athletes (VA). Methods We recruited 314 predominantly Caucasian VA's with a history of endurance exercise and no traditional risk factors for coronary artery disease. Participants underwent a 12-lead electrocardiogram, cardiopulmonary exercise testing (CPET), 24-hour Holter monitoring, and cardiac magnetic resonance imaging (CMR). fQRS was categorized as &amp;gt;2 consecutive leads using established criteria (1). Results fQRS in 2 or more contiguous leads was identified in 12% of VA's. The presence of fQRS was more prevalent in males and increased with age (p &amp;lt; 0.05). There were no significant differences in ECG conduction indices. When CMR parameters were considered, the presence of fQRS was associated with increased left ventricular (LV) mass index and increased right ventricular (RV) function. There was no relationship with the presence of late gadolinium enhancement. Athletes with fQRS achieved a significantly lower predicted peak VO2 and trended towards lower peak resistance on CPET. No relationship was observed with total ventricular premature beat count or the presence of complex ectopy on 24-hour Holter monitoring. Conclusions fQRS in 2 or more contiguous leads is commonly present amongst male Caucasian VA’s, and its prevalance increases with age. It is associated with greater LV mass and increased RV ejection fraction. Athletes with fQRS may achieve a lower percentage predicted VO2 max compared to those without. Furthermore, FQRS did not predict late gadolinium enhancement, increased VPB count or complex ectopy.Comparing VAs with FQRSQRS-fragmentation patterns (Das et al)

Validation of Two-Minute Step Test and Development of VO2max Prediction Equation in Older Korean Adults

PURPOSE This study aimed to verify the criterion validity of the two-minute step test in older Korean adults, develop an equation for predicting VO&lt;sub&gt;2max&lt;/sub&gt;, and verify cross-validation.METHODS A submaximal exercise test and the two-minute walk test were performed on 150 older adults (74 males and 74 females) aged 65 years or older. Correlation analysis was performed to confirm criterion validity. An equation for estimating VO&lt;sub&gt;2max&lt;/sub&gt; was developed through multiple regression analysis, and cross-validation was confirmed by performing a correlation analysis between measured and predicted values of VO&lt;sub&gt;2max&lt;/sub&gt;.RESULTS The correlation coefficient between VO&lt;sub&gt;2max&lt;/sub&gt; and the two-minute step test was 0.457 (p&lt;.001). The adjusted R&lt;sup&gt;2&lt;/sup&gt; of the developed VO&lt;sub&gt;2max&lt;/sub&gt; prediction equation was 0.430 (p&lt;.001), and the explanatory variables finally selected were sex, age, number of steps in the two-minute step test, and percentage of body fat. The correlation coefficient between the measured VO&lt;sub&gt;2max&lt;/sub&gt; (19.08±4.36) and the predicted VO&lt;sub&gt;2max&lt;/sub&gt; (19.73±3.36) was 0.654 (p&lt;.001).CONCLUSIONS This study confirmed the criterion validity of the two-minute step test in older Korean adults, and the cross-validation of the developed VO&lt;sub&gt;2max&lt;/sub&gt; prediction formula was verified. The explanatory variables of the prediction equation will be easy to apply in the field, and more meaningful results will be derived if the validity of the prediction equation developed for a larger number of participants is verified.

Validation of 6-Minute Walk Test and Development of VO2max Prediction Equation in the Elderly

vPURPOSE: Cardiorespiratory fitness is closely related to cardiovascular and chronic diseases and is an important predictor of mortality. Despite the significance of cardiorespiratory fitness, currently, a lack of research exists that validates the effectiveness of the 6-minute walk test, specifically in the Korean population. Therefore, the purpose of this study was to verify the validity of the 6-minute walk test for Korean older individuals and to develop a maximum oxygen consumption (VO&lt;sub&gt;2max&lt;/sub&gt;) prediction equation.METHODS: A total of 167 participants were included in the final analysis, after excluding 33 of the 200 participants. Moreover, VO&lt;sub&gt;2max&lt;/sub&gt; was measured by performing a submaximal exercise test on a treadmill, and the total distance and heart rate were measured using a 6-minute walk test. Pearson’s correlation coefficient was calculated to verify the criterion validity between VO&lt;sub&gt;2max&lt;/sub&gt; and total distance in the 6-minute walk test. To develop a VO&lt;sub&gt;2max&lt;/sub&gt; prediction equation, multiple regression analysis was conducted and cross-validation of the developed prediction equation was confirmed.RESULTS: The correlation coefficient between VO&lt;sub&gt;2max&lt;/sub&gt; and the 6-minute walk test was 0.575 (&lt;i&gt;p&lt;/i&gt;&lt;.001). The adjusted R2 of the VO&lt;sub&gt;2max&lt;/sub&gt; prediction equation using the 6-minute walk test was 0.449 (&lt;i&gt;p&lt;/i&gt;&lt;.001). The difference between the predicted VO&lt;sub&gt;2max&lt;/sub&gt; and measured VO&lt;sub&gt;2max&lt;/sub&gt; was 1.184±1.331 mL/kg/min, and the correlation coefficient was 0.594 (&lt;i&gt;p&lt;/i&gt;&lt;.001).CONCLUSION: The developed prediction equation consisted of explanatory variables that can be measured easily and were practical in the field. As entry into a post-aged society is imminent, managing older adult’s physical fitness has become a significant issue. In the future, if the validity verification is performed with a large number of people, the prediction formula developed in this study will be useful.

Maximal oxygen uptake prediction from submaximal bicycle ergometry using a differential model

The maximal oxygen uptake (VO2max) estimation has been a subject of research for many years. Cardiorespiratory measurements during incremental tests until exhaustion are considered the golden yard stick to assess VO2max. However, precise VO2max determination based on submaximal tests is attractive for athlete as well for clinical populations. Here, we propose and verify such a method based on experimental data. Using a recently developed model of heart rate (HR) and VO2 kinetics in graded exercise tests, we applied a protocol, which is terminated at 80% of the estimated maximal HR during ergometer cycling. In our approach, initially, formula for maximal HR is selected by retrospective study of a reference population (17 males, 23.5 ± 2.0 years, BMI: 23.9 ± 3.2 kg/m2). Next, the subjects for experimental group were invited (nine subjects of both sexes: 25.1 ± 2.1 years, BMI 23.2 ± 2.2 kg/m2). After calculation of maximal HR using cardiorespiratory recordings from the submaximal test, VO2max is predicted. Finally, we compared the prediction with the values from the maximal exercise test. The differences were quantified by relative errors, which vary from 1.2% up to 13.4%. Some future improvements for the procedure of VO2max prediction are discussed. The experimental protocol may be useful for application in rehabilitation assessment and in certain training monitoring settings, since physical exertion is not a prerequisite and the approach provides an acceptable VO2max estimation accuracy.

COVID-19 reduces cardiorespiratory fitness even months after a mild to moderate acute phase: a retrospective cohort study

Background COVID-19 survivors may experience long-term health problems, including deterioration of cardiorespiratory fitness (CRF), as demonstrated by several cross-sectional studies that compared the results of cardiopulmonary exercise tests (CPET) performed only after COVID-19 with predicted values. This study aimed to analyze a change in CRF between repeated CPETs in response to suffered COVID-19. Methods A total of 127 healthcare workers (HCWs; mean age 55.7 years) underwent two CPETs with a mean interval of 762 days. Forty HCWs suffered from COVID-19 (mild to moderate severity) in the interim (321 days before the second CPET), and 87 HCWs formed a control group. Mixed-effects regression with multiple adjustment and interaction terms was used for two response variables – maximum oxygen uptake (VO2 max) and power output. Results Between both CPETs, mean VO2 max decreased statistically significantly in the COVID-19 subgroup (by 3.12 mL/kg/min, p = .034) and insignificantly in controls (by 0.56 mL/kg/min, p = .412). The proportion of HCWs achieving predicted VO2 max decreased from 75.9% to 59.5% (p = .161) in COVID-19 survivors, while it increased from 73.8% to 81% (p = .274) in controls. COVID-19 (β = −0.66, p = .014) and body mass index (β = −0.49, p < .001) were independent negative predictors of VO2 max change. COVID-19 was not associated with a change in power output. Conclusions On the basis of repeated CPETs, COVID-19 significantly, albeit rather modestly, reduces CRF almost one year after infection. The reduction persists even after the acute phase with mild or moderate severity.

Right Ventricle Myocardial Work in ToF-repair survivors: no longer behind the scenes

Abstract Funding Acknowledgements Type of funding sources: None. Background Tetralogy of Fallot is the most common cyanotic CHD and survivors after ToF repair are growing rapidly. Children and, more frequently, young adults spToF develop late complications: life-threatening ventricular arrhythmias and SCD remain a great concern in these patients. This study has the aim to analyse advanced Right Ventricle echocardiographic and CMR features sp-ToF in the long-term follow-up, finding non-invasive predictors of adverse prognosis. Methods This is a retrospective cohort study. 240 patients sp-ToF were included (mean age 13 ± 11 years). The electrocardiographic, echocardiographic, CMR and CPET data were reviewed retrospectively. Non-invasive RV Global myocardial Work Index (RVGWI) was calculated as the area of the RV pressure-strain loops. RV Global Constructive Work (RVGCW), RV Global Wasted Work (RVGWW) and RV Global Work Efficiency (RVGWE) were estimated. Patients were screened according to age at surgery, time since the radical repair at the follow-up, increased estimated RV systolic pressure, differences in instrumental findings after PVrep. A composite end-point of MACEs (syncope, sustained and non-sustained ventricular tachycardia, sudden cardiac death) was used. Results Older patients at surgery (≥12 months) have significantly reduced VO2 max at CPET, larger RA and LA areas and larger RV basal diameter. CPET values are not significantly different in patients with more than 25 years since the corrective surgery but echo and CMR-LVEF measured are slightly but significantly reduced and RVGWE is significantly lower. Patients with RVSP ≥ 60 mmHg have significantly higher RVGWW, worst RV FWLS, lower RVGCW and RVGWE. Patients who have undergone PVrep show improvement in RV GLS, RV FWLS and RVGWE and a RVGWW reduction. As reguards the CMR RV volume evaluation sp-ToF, patients with RVESVi ≥80ml/m2 have lower RVGWE and show an inverse correlation between RVEDVi and RVGWE. Sp-ToF patients with borderline/impaired predicted VO2 max at CPET have a reduced RV FWLS, higher RVGWW and an inverse correlation between METs and RVGWW. Patients who have suffered MACEs (2 NS-TV, 3 S-TV, 7 syncopes, 8 sudden deaths) hadsignificant impairment of RV systolic function (FAC, RV FWLS, CMR-RVFE), significantly higher RVGWW, lower RVGWE and RVGWI. Conclusion Long-term survival and clinical condition sp-ToF in infancy are generally good and late functional status in survivors could be excellent up to 25 years after radical correction. However, older patients at surgery have relative reduced functional status compared with those undergoing early repair. The advanced echocardiographic and CMR evaluation of RV function sp-ToF are usually related to worse prognosis, VT and reduced functional status. RV myocardial work evaluation is feasible in patients with repaired ToF, it may be a more sensitive indicator of RV fuctional impairment compared with standard echocardiographic parameters and is able to predict exercise capacity.