Postexercise Hypotension, Aortic Pressure And Autonomic Modulation In Men Living With Hiv

Abstract

A single session of aerobic exercise reduces blood pressure vs. pre-exercise, which is referred as postexercise hypotension (PEH). Changes in cardiac autonomic control and local vasodilatation contribute to PEH. HIV-infected patients present higher risk of hypertension, autonomic and endothelial dysfunction, which may influence the PEH. However, this phenomenon has never been studied in this population. PURPOSE: To investigate the effects of acute aerobic exercise upon systemic blood pressure, aortic pressure, and cardiac autonomic modulation in men living with HIV. METHODS: After cardiopulmonary exercise testing, 10 HIV-infected (HIV: 47.5 ± 9.7 yrs; 25.2 ± 3.0 kg.m-2) and 14 healthy men (CTL: 40.1 ± 10.5 yrs; 25.8 ± 3.4 kg.m-2) underwent cycling bouts expending 150 kcal at 50% oxygen uptake reserve (time to achieve 150 kcal - HIV: 24.1 ± 5.5 and CTL: 23.1 ± 3.0 min) and control sessions (20 min), in a randomized counterbalanced order. Systolic blood pressure (SBP), aortic pressure, and heart rate variability were assessed 30 min before and 60 min after each session, by means of oscillometric digital monitor, pulse wave reflection (tonometry), and beat-to-beat heart rate intervals, respectively. Comparisons within-between sessions were made using 2-way ANOVA with repeated measures (P ≤ 0.05). RESULTS: No difference was detected between groups for maximal oxygen uptake (HIV: 27.3 ± 4.2 vs. CTL: 31.4 ± 6.8 mL·kg-1·min-1; P= 0.1) and SBP at rest (HIV: 117.2 ± 11.6 vs. CTL: 112.2 ± 8.9 vs mmHg; P= 0.2). Resting aortic pressure was higher in HIV (107.0 ± 9.3 mmHg) vs. CTL (100.0 ± 4.3 mmHg; P= 0.03), while standard deviation of NN intervals (SDNN) was lower in HIV (28.3 ± 11.2 ms) vs. CTL (43.9 ± 20.8 ms; P= 0.04). In CTL, SBP (-9.3 ± 5.9 mmHg; P= 0.01), aortic pressure (-6.3 ± 4.6 mmHg; P= 0.03), and SDNN (-23.4 ± 44.5 ms; P= 0.05) decreased after submaximal exercise vs. control sessions. No significant change occurred in HIV for SBP (-4.2 ± 18.9 mmHg; P= 0.5), aortic pressure (-5.1 ± 13.0 mmHg; P= 0.2), or SDNN (+5.5 ± 25.6 ms; P= 0.4). CONCLUSION: Healthy, but not HIV-infected men, exhibited acute blood pressure reduction after submaximal aerobic exercise. The higher central arterial stiffness and lower vagal modulation among HIV patients may help to explain the absence of PEH in this group. Supported by FAPERJ Grant.