Baroreflex sensitivity assessment during acute high-intensity inspiratory endurance exercise

Background/Aims: The association between respiration and inspiratory resistance load leads to changes in cardiovascular dynamics and autonomic control. However, the acute effects of high-intensity inspiratory exercise on autonomic cardiovascular control assessed by the baroreflex sensitivity (BRS) have not been reported. Thus, the aim of this study was to characterize the BRS response during high-intensity inspiratory endurance exercise. Methods: Twenty healthy men (24±3 years) were submitted to a maximal inspiratory pressure (MIP) assessment; a progressive threshold loading test to set the maximal load sustained for at least 1 minute (PThMAX) and to different high-intensity inspiratory endurance exercises (80%, 95%, 100%PThMAX and the critical inspiratory power). They were performed until task failure (TLIM) using a linear inspiratory load resistor (PowerBreathe® K5). The BRS was assessed during inspiratory endurance exercise and under rest conditions (SHAM, WITH and WITHOUT mouthpiece) using transfer function spectral analysis (αFT(BF)) (PORTA, A. et al. Journal of Applied Physiology 2013; 115(7):1032-42). Results: There was a decrease in BRS during high-intensity inspiratory endurance exercise when compared to rest conditions (p Conclusions: The BRS response showed interaction between the cardiovascular oscillations and pulmonary dynamics during inspiratory exercise. This may contribute to the evaluation and prescription of an inspiratory training program to improve the sensitivity of the baroreceptors. Funding: CNPq #480067/2012-0.