Inspiratory muscle metaboreflex increases blood pressure in eutrophic and obese individuals

Abstract

Introduction: Metaboreflex, activated by the accumulation of metabolites during exercise, leads to peripheral vasoconstriction, increasing the blood pressure. Obese individuals have decreased inspiratory muscle endurance, which suggests an early accumulation of metabolites and, consequently, alterations in inspiratory muscle metaboreflex. Objective: To compare the hemodynamic responses mediated by the inspiratory muscle metaboreflex in obese and eutrophic individuals. Method: Twenty obese (31 ± 6 years old, ten males, 37.5 ± 4.7 kg/m2) and twenty eutrophic individuals (29 ± 8 years old, ten males, 23.2 ± 1.5 kg/m2) were included in this study and submitted to respiratory muscle strength evaluation through manovacuometry. Inspiratory muscle metaboreflex was induced by resistive exercise at 60% maximal inspiratory pressure sustained until exhaustion. The control protocol consisted of breathing without inspiratory resistance (zero cmH2O) sustained for 30 minutes. Blood pressure and heart rate were measured throughout the protocols, on different days and in a randomized order. Results: The inspiratory muscle metaboreflex activation induction protocol led to a similar increase in systolic, diastolic and mean blood pressures, as well as heart rate in obese and eutrophic individuals. As expected, the hemodynamic variables remained unaltered in the control protocol. Conclusion: Inspiratory muscle strength did not differ (p = 0.814) between obese and eutrophic individuals. This study suggests that obese individuals present hemodynamic responses induced by the inspiratory muscle metaboreflex, similar to eutrophic individuals.