RELAÇÃO ENTRE EFICIÊNCIA VENTILATÓRIA E RESPOSTAS CARDIOMETABÓLICAS DO EXERCÍCIO EM ATLETAS

Abstract

Ventilatory efficiency can be defined by the minute ventilation level related to the carbon dioxide pulmonary elimination (V’E/V’CO2) during a cardiopulmonary exercise test (CPET). Its role and importance in sports performance remain unclear, both because of high V’E/V’CO2 levels found in athletes, compatible with ventilatory inefficiency even in the absence of cardiopulmonary disease, and because of the evidence of the lack of relationship between V’E/V’CO2 and maximal oxygen uptake (V’O2 max). A new efficiency ventilatory method was reported, which takes into account the CO2 removal rate for each 10-fold increase in minute ventilation, corrected for the maximum theorical CO2 removal rate at the maximum voluntary ventilation predicted level. Thus, we assume that the method would reveal association between ventilatory efficiency and CPET cardiometabolic parameters, in correspondence with aerobic fitness. Objective: to analyze the relationship between ventilatory efficiency and cardiometabolic responses to exercise, V’O2 max and O2 Pulse (PuO2), in athletes, through the ventilatory efficiency new methods, CO2-ACR and ŋV'E and also the conventional V’E/V’CO2 slope and V’E/V’CO2 nadir, in addition to exploring the association between ventilatory efficiency indices and athletes’ performance. Methods: observational, cross-sectional and retrospective study, on databases, secondary to two studies, MEDALHA and BRASÍLIA, in which its participants (61 subjects) performed to a maximal incremental CPET, and the variables of ventilatory efficiency, PuO2 and V’O2 max, were collected for correlation analysis (Pearson/Spearman). In addition, individuals were divided into groups according to V’O2 and PuO2 values, with the cut-off point being 57.8 ml/min/Kg and 11.5 ml/beat/m2, respectively, for later comparison data ventilatory efficiency (Student t Test). To extend the knowledge of the ventilatory efficiency and performance association, we analyzed the 10Km running time in 25 runners. Results: CO2-ACR ventilatory efficiency index values showed a significant difference according to the V’O2 groups (6.7 ± 1.8; 7.9 ± 2.5, p = 0.024) and also with regard of PuO2 groups (6.8 ± 1.9; 8.0 ± 2.4, p = 0.004). CO2-ACR was higher in younger subjects with lower Body Mass Index (BMI), this population had higher V’O2, as expected, but also higher ventilatory efficiency. CO2-ACR also showed a positive correlation with V’O2 (r = 0.325; p=0.010) and PuO2 (rhô = 0.411, p = 0.001). Thus, we concluded that the the new metric for ventilatory efficiency showed, in general, a greater assossiation with CPET cardiometabolic variables in athletes. There was a moderate and negative correlation between athletes performance in the 10 Km runnig and Slope 1 ventilatory effeciency index.