Minute-Ventilation Variability during Cardiopulmonary Exercise Test is Higher in Sedentary Men Than in Athletes

Abstract

BackgroundThe occurrence of minute-ventilation oscillations during exercise, named periodic breathing, exhibits important prognostic information in heart failure. Considering that exercise training could influence the fluctuation of ventilatory components during exercise, we hypothesized that ventilatory variability during exercise would be greater in sedentary men than athletes.ObjectiveTo compare time-domain variability of ventilatory components of sedentary healthy men and athletes during a progressive maximal exercise test, evaluating their relationship to other variables usually obtained during a cardiopulmonary exercise test.MethodsAnalysis of time-domain variability (SD/n and RMSSD/n) of minute-ventilation (Ve), respiratory rate (RR) and tidal volume (Vt) during a maximal cardiopulmonary exercise test of 9 athletes and 9 sedentary men was performed. Data was compared by two-tailed Student T test and Pearson´s correlations test.ResultsSedentary men exhibited greater Vt (SD/n: 1.6 ± 0.3 vs. 0.9 ± 0.3 mL/breaths; p < 0.001) and Ve (SD/n: 97.5 ± 23.1 vs. 71.6 ± 4.8 mL/min x breaths; p = 0.038) variabilities than athletes. VE/VCO2 correlated to Vt variability (RMSSD/n) in both groups.ConclusionsTime-domain variability of Vt and Ve during exercise is greater in sedentary than athletes, with a positive relationship between VE/VCO2 pointing to a possible influence of ventilation-perfusion ratio on ventilatory variability during exercise in healthy volunteers.

Left ventricular diastolic dysfunction and exertional ventilatory inefficiency in COPD

“…Based on our original premise of change in minute-ventilation and ventilatory efficiency through altered central hemodynamics during exercise in COPD/LVDD compared to controls, we expected a significant loss of fractal properties in this group. In healthy people, V´E/V´CO 2 correlated positively and significantly with V T variability, pointing to a possible influence of the ventilation-perfusion ratio on ventilatory variability in healthy volunteers [29]. We did not confirm this correlation for COPD (data not shown).…”

“…The tricuspid reflux velocity was obtained through continuous Doppler at the right ventricle inlet, and the pulmonary arterial systolic pressure was calculated with the addition of 10 mmHg of pressure in the right atrium. Final diagnosis and classification of LVDD was based on standard guidelines 29 and with septal and lateral e' adjusted by age [28].…”

“…In our case, we carried out the calculation in order to establish ventilatory variability. This is based on expected curvilinear behavior of ventilation when plotted against time during a progressively increasing work-rate exercise above the anaerobic threshold [29]. The quantitative analysis of a plot entails fitting an ellipse to the plot, with its center coinciding with the center point of the markings and comparing points from two lines traversing through the center point of the data, longitudinal and transverse.…”

“…Thus, the Poincaré index (SD1, SD2) was computed. As variability metrics depend on the number of respiratory cycles during the evaluation period, we divided the SD1 and SD2 by the number of breath-by-breath measured data collected for each subject (SD1/n and SD2/n) as recommended [29].…”

Breathing Patterns of Healthy Human Response to Different Levels of Physical Activity

“…Relation between minute ventilation and oxygen uptake at peak treadmill exercises was constructed for the study. Treadmill has been commonly used to investigate cardiorespiratory responses to physical activities [9,10,11]. Wu et al [12] used a finite state model to quantify respiratory motion characteristics.…”