Long-term stability of the oxygen pulse curve during maximal exercise

Abstract

INTRODUCTION:Exercise oxygen pulse (O2 pulse), a surrogate for stroke volume and arteriovenous oxygen difference, has emerged as an important variable obtained during cardiopulmonary exercise testing.OBJECTIVES:We hypothesized that the O2 pulse curve pattern response to a maximal cycling ramp protocol exhibits a stable linear pattern in subjects reevaluated under the same clinical conditions.METHODS:We retrospectively studied 100 adults (80 males), mean age at baseline of 59 ± 12 years, who performed two cardiopulmonary exercise testings (median interval was 15 months), for clinical and/or exercise prescription reasons. The relative O2 pulse was calculated by dividing its absolute value by body weight. Subjects were classified into quintiles of relative O2 pulse. Cardiopulmonary exercise testing results and the O2 pulse curve pattern, expressed by its slope and intercept, were compared among quintiles of relative O2 pulse at both cardiopulmonary exercise testings.RESULTS:After excluding the first minute of CPX (rest-exercise transition), the relative O2 pulse curve exhibited a linear increase, as demonstrated by high coefficients of determination (R2 from 0.75 to 0.90; p<0.05 for all quintiles). Even though maximum oxygen uptake and relative O2 pulse were significantly higher in the second cardiopulmonary exercise testing for each quintile of relative O2 pulse (p<0.05 for all comparisons), no differences were found when slopes and intercepts were compared between the first and second cardiopulmonary exercise testings (p>0.05 for all comparisons; except for intercept in the 5th quintile).CONCLUSION:Excluding the rest-exercise transition, the relative O2 pulse exhibited a stable linear increase throughout maximal exercise in adults that were retested under same clinical conditions.

Cardiology in Brazilian scientific journals: an overview

“…Conversely, with the recent association of physical inactivity with chronic disease, these data may also suggest that increases in sympathetic nervous system activity contribute to the increased incidence of cardiovascular diseases associated with a sedentary lifestyle. Oliveira et al [34], in view of the fact that exercise oxygen pulse (O pulse), a surrogate for stroke volume and arteriovenous oxygen difference, has emerged as an important variable obtained during cardiopulmonary exercise testing hypothesized that the O pulse curve pattern response to a maximal cycling ramp protocol exhibits a stable linear pattern in subjects reevaluated under the same clinical conditions. Their findings show that, excluding the rest-exercise transition, the relative O pulse exhibited a stable linear increase throughout maximal exercise in adults that were retested under same clinical conditions.…”

Ponto ótimo cardiorrespiratório: uma variável submáxima do teste cardiopulmonar de exercício

“…During a maximum Cardiopulmonary Exercise Testing (CPET), different ventilatory data are obtained with clinical, diagnostic and/or prognostic implications 1 , such as maximum oxygen consumption (VO 2 max) -an objective measure of cardiorespiratory function 2,3 -the maximum oxygen pulse, both absolute and relative to body weight 4,5 , the anaerobic threshold (AT) 6 , the ventilatory equivalent for carbon dioxide (VE/VCO2) 7 and the curve generated by the oxygen uptake efficiency slope (OUES) 8 . However, there are several limitations with the measurement of these variables, such as low reproducibility 9 , different manners of calculation or identification 10 , and the fact that to obtain most of these, it is necessary to perform a truly maximum test 11,12 , which usually depends the motivations of the evaluator and the evaluated.…”

Comparison of High Intensity Interval to Moderate Intensity Continuous Aerobic Exercise on Ventilatory Markers in Coronary Heart Disease Patients: A Randomized Controlled Study

“…It has shown that recent studies have evaluated the impacts of different intensities of aerobic training, performed by patients with coronary heart disease [6,7]. Also, a recent review has explained that HII program was more effective than continuous exercise program in patients with CHD [8]. The current study illustrated that different intensities of aerobic exercise could be able to enhance O 2 P peak in patients with CHD [6].…”