Efeitos da CPAP na duração do exercício e nas variáveis ventilatórias em indivíduos saudáveis

Abstract

Continuous positive airway pressure (CPAP) is used as a tool to unload respiratory muscle during high-intensity exercise, and consequently, improve performance. However, studies link the improvement in performance not only to interventions but also to confounding factors such as expectation. The aim of this study was to evaluate if the presence of a commercial CPAP during a graded maximal test, under either negative (CPAPn, n=7) or positive (CPAPp, n=7) expectations induced by the instructions, would affect physical performance of healthy men comparing to a control group (n=9) and to a prior visit without CPAP interventions or instructions in the three groups (visit 1 vs. visit 2). No significant differences were found in exercise duration (median (IQR), visit 1 vs. visit 2: CPAPn - 538.3 (126.6) s vs. 508.5 (163.8) s; CPAPp - 470.3 (61.7) s vs. 506.0 (85.8) s), taken as the main outcome, in maximal oxygen uptake and in perceived exertion among groups comparing the visits. A significant reduction in minute ventilation for CPAP groups (median (IQR), visit 1 vs. visit 2: CPAPn - 107.0 (21.5) L.min-1 vs. 86.6 (23.2) L.min-1 ; CPAPp - 112.3 (19.9) L.min-1 vs. 91.8 (18.1) L.min-1 ) was seen. In conclusion, CPAP delivered by a commercial device did not improve the performance and reduced minute-ventilation of healthy subjects during a maximal graded test.