ACUTE POST-DYNAMIC, ISOMETRIC AND COMBINED RESISTANCE EXERCISE HYPOTENSION IN PATIENTS WITH HYPERTENSION: A RANDOMIZED STUDY

Abstract

Objective: American guidelines included dynamic resistance exercise (DRE) and isometric handgrip (IH) in hypertension treatment. A single session of DRE decreases blood pressure (BP) during the recovery period, which has been described as post-exercise hypotension (PEH). However, the occurrence of PEH after a session of IH is controversial and the post-exercise effects of the association of DRE and IH, in a combined resistance exercise (CRE), has not been evaluated. Thus, this study investigated the effects of DRE, IH and CRE on post-exercise BP and its hemodynamic, autonomic and vascular mechanisms. Design and method: Seventy medicated hypertensive men (52 ± 8 years) were randomly allocated to perform 1 of 4 interventions: DRE (8 exercises, 3 sets, 50%1RM, repetitions until moderate fatigue), IH (4 sets, 2 min-unilateral contraction, 30% MVC), CRE (DRE + IH) and control (CO - seated resting). Office BP, systemic hemodynamics (CO2 rebreathing technique), cardiovascular autonomic modulation [spectral analysis of heart rate (HR) and BP variabilities] and brachial vascular parameters (ultrasound) were evaluated before and after the interventions. Thus, the responses to interventions (post – pre-intervention values) were calculated and compared among the groups by ANOVAs with significance level set at P < 0.05. Results: Responses to IH were similar to CO, showing that a single session of IH did not promote PEH, and did not affect any of the BP mechanisms. On the other hand, DRE and CRE induced responses significantly different from IH and CO. DRE and CRE significantly decreased systolic BP, diastolic BP, mean BP, stroke volume and cardiac baroreflex sensitivity, while they significantly increased HR, brachial artery diameter, blood flow and vascular conductance during the post-exercise period. Additionally, DRE significantly decreased post-exercise cardiac vagal modulation (HFR-R, nu) and increased cardiac sympathovagal balance (LF/HF). Conclusions: DRE, but not IH, elicits PEH, which is accompanied by vasodilation and increased HR, via a higher sympathovagal balance and lower baroreflex sensitivity. The addition of IH to DRE, in a CRE, does not potentiate PEH and did not change its mechanisms.