Efeito da ativação metaborreflexa muscular sobre as respostas cardiovasculares de homens vivendo com HIV/AIDS

Abstract

Introduction: People living with HIV frequently present autonomic dysfunction at rest and during recovery after exercise. Considering that autonomic nervous system is an important neuromodulator that regulates both heart rate and arterial pressure, it is expected a full integrity of this system to achieve a proper cardiovascular response during exercise. Thus, it would be reasonable to assume that HIV-infected patients exhibit altered neurovascular responses to exercise. Objective: Evaluate the influence of muscle metaboreflex upon the pressor response during handgrip exercise in men living with HIV/AIDS. Methods: Pressor and heart rate responses were evaluated during metaboreflex activation by means of the post-exercise muscle ischemia (PEMI) method and control exercise session (CER) in 17 HIV-infected patients and 21 healthy controls. The protocols were performed randomly on the same day, being both sessions composed of 12 min, as follows: a) 3 min at rest, b) 3 min of dynamic handgrip exercise at 30% of maximal voluntary contraction, c) 3 min of recovery post-exercise with vascular occlusion (occlusion only in PEMI), and d) 3 min of recovery post-exercise without vascular occlusion. To assess the metaboreflex gain, the difference between PEMI and CER in the last 2 minutes of recovery post-exercise with vascular occlusion were calculated for blood pressure and heart rate. Results: Systolic and mean blood pressure (p < 0.01) were superior in the last 2 min of recovery with vascular occlusion at PEMI in relation to CER for both groups. No difference was found between groups for systolic, mean and diastolic blood pressure, and heart rate (p > 0.05). However, metaboreflex gain (PEMI CER) for systolic blood pressure in HIV-infected patients were lower than healthy controls (HIV: 4.05 ± 4.63 vs Controls: 7.61 ± 3.99 mmHg; P = 0.01). Conclusion: Men living with HIV/AIDS may exhibit impaired muscle metaboreflex sensibility to dynamic handgrip exercise