Influência da aptidão aeróbia e da idade sobre variáveis do teste de exercício cardiopulmonar de homens aparentemente saudáveis

Abstract

Introduction: the practice of regular physical exercise favors beneficial changes in several organic systems, mitigating the deleterious effects of aging. The cardiopulmonary exercise test (CPET) allows verifying the responses resulting from the integration of the cardiovascular, respiratory and muscular systems, allowing the extraction of predictive variables of health and physical conditioning such as peak oxygen consumption (V̇O2PEAK), peak heart rate (HRPEAK), peak systolic arterial pressure (SAPPEAK), peak diastolic arterial pressure (DAPPEAK), peak relative power (W/kgPEAK), peak carbon dioxide production (V̇CO2PEAK), peak exhaled minute volume (V̇EPICO), slope of oxygen consumption efficiency ( OUES), slope of the ventilatory carbon dioxide equivalent (V̇E/V̇CO2slope), ratio between the relative increase in oxygen consumption and the relative increase in load (ΔV̇O2/ΔW), oxygen pulse (V̇O2/HR), oxygen consumption in the anaerobic threshold (V̇O2AT) and time required for a 50% drop in the peak V̇O2 reached in CPET (T1/2V̇O2PEAK). Such variables studied simultaneously are important indicators of the integrity and health of these systems and can provide important and complementary outcomes considering the influence of physical exercise and age in the organism. Objective: To investigate the influence of regular aerobic physical exercise and age on the set of variables obtained in CPET simultaneously: V̇O2PEAK, HRPEAK, SAPPEAK, DAPPEAK, W/kgPEAK, OUES, V̇EPEAK, T1/2V̇O2PEAK, V̇CO2PEAK, V̇E/V̇CO2slope, V̇O2AT, ΔV̇O2/ΔW and V̇O2/HR. Methods: Forty apparently healthy men were divided into four groups: young trained group (YTG), young untrained group (YUT), middle aged trained (MTG) and middle aged untrained (MUG). Individuals aged 20-30 years and 50-60 years were considered young and middle-aged, respectively. Individuals who practiced at least 150 minutes of aerobic physical exercise per week for 6 uninterrupted months and with a classification of “good” or above according to the American Heart Association (AHA) for relative V̇O2PEAK and who participated in sports events were considered trained. Individuals who did not meet these requirements and who had a “regular” or lower classification according to the AHA for V̇O2PEAK were classified as untrained. All underwent CPET with a ramp-type protocol on an electromagnetic braking cycle ergometer to obtain cardiorespiratory and metabolic variables. Two-way ANOVA or Student's t test were used to compare groups between groups for variables that did not reach homogeneity, considering a p value < 0.05. Results: The groups had different profiles. In addition to the significant differences observed for the age and training factors as a result of the different levels of aerobic fitness and integrity of the systems, the interaction between the factors observed for the variables V̇O2AT (absolute and relative), W/kgPEAK, OUES and T1/2V̇O2PEAK. For the first two variables, the age factor did not show significant differences between YUT and MUG, while for OUES, this same factor was not significant for any comparison. For the T1/2V̇O2PEAK, the training factor was only significant for the young groups. Conclusion: The age and level of physical activity of individuals directly affect variables related to aerobic fitness and systemic integrity, however, the variables V̇O2AT, W/kgPEAK, OUES and T1/2V̇O2PEAK seem to be affected differently depending on age and the level of physical activity of the individual.