A influência de diferentes intensidades de esforço sobre as respostas cardiorrespiratórias e psicofisiológicas em exercícios físicos até a exaustão

Abstract

The physical exercise induces multiple metabolic and psychophysiological changes that depend on the type, volume and intensity domains of the exercise, requiring greater load control in order to generate specific adaptations. The present study aimed to compare the psychophysiological and cardiorespiratory responses of exercises at different intensities until exhaustion. As a specific objective, the project sought to relate respiratory variables with the Subjective Perceived Exertion (RPE). Quasi-experimental study, with non-random distribution and no control group. Nine participants were evaluated (men, active, with a mean age of 28 years (± 6,8), body mass: 74.96±8.05 kg, height: 173.34±4.46cm). On the first visit, an incremental test was performed to determine the second metabolic threshold (LM2). The subsequent sessions were randomized, with two time-to-exhaustion tests being performed with (i) intensity of 80% of LM2 (intense intensity) and (ii) intensity of 120% of LM2 (severe intensity). Were continuously monitored the cardiorespiratory variables (respiratory rate -RR, tidal volume - VT and heart rate - FC) and collected every 2min RPE using the BORG Scale (CR-10), affective valence scale ( EVA: +5, -5) and activation (EA: 6,1). The variables were divided into quartiles, ranging from the minimum value, 25%, 50%, 75% and the maximum (Q1-Q5). Interquartile ranges were compared between intensities using Student`s t-test and Bonferroni`s post hoc test. The Pearson correlation (r) and the R² of the linear regression were calculated between the cardiorespiratory variables and, in the case of psychometric scales that are discreet, the Spearman test was used. Statistical significance was set at p 0.9 and a positive and significant relationship with RPE, showing that the nature of exhaustion influences these results. It is concluded that the tolerance time of exhaustion exercises are intensity dependent and are not proportional. Furthermore, alterations at the beginning of exercise with severe intensity could be related to vagal inhibition that would generate a greater impact on the magnitude of heart rate responses, perceived exertion and affective valences.