Efeitos agudos do exercício isométrico de handgrip na variabilidade da pressão arterial e na função e regulação cardiovascular em pessoas com hipertensão arterial sistêmica: um ensaio clínico cruzado

Abstract

Blood pressure variability (BPV) is an important predictor of cardiovascular mortality. Reductions in BVP in hypertensive patients can minimize the risk of cardiovascular events. The isometric handgrip exercise (IHE) is effective in reducing blood pressure (BP) in hypertensive patients and appears as an alternative strategy that is easy to apply. Acute cardiovascular responses after EIH predict chronic adaptations in BP regulation. However, the acute effects of EIH on BVP are unknown. Therefore, the objective of the study was to verify the acute effect of an isometric handgrip exercise session on blood pressure variability and cardiac autonomic modulation in hypertensive patients. In this randomized crossover clinical trial, 45 patients participated, 62.3% women, aged 58.0 ± 10.5, randomized (1:1) into IHE (n = 45) and SHAM (n = 45) conditions. When EIH performed 4 sets of 2 minutes of isometric contraction, with 1 minute interval, at 30% of the maximum contraction. When SHAM, they followed the same conditions as EIH, using an anti-stress ball. BVP was assessed by real mean variability (RMV) and standard deviation (SD) for systolic (SBP) and diastolic (DBP) blood pressure, after session, by MAPA (Dyna-MAPA, Cardios, Brazil). Cardiac autonomic modulation (CAM) was assessed by heart rate variability (HRV) in the time and frequency domains, in the moments before and after IHE, using the Polar Vantage M2 heart rate monitor with Polar H10 strap. Independent T Test and GEE were used for comparison analysis and model analysis, with a value of P<0.05 being adopted as significant. There was no significant difference in BVP of SBP SHAM x IHE: MRV (8.96 mmHg ± 1.97 x 8.88 mmHg ± 2.04, p = 0.85), SD (13.17mmHg ± 3.68 x 13 .07 mmHg ± 3.89, p = 0.89). DBP BVP did not demonstrate significant differences between SHAM x IHE: RMV (7.13 mmHg ± 1.62 x 6.80 ± 1.21, p = 0.27), SD (10.27 mmHg ± 2.35 x 10.17 ± 2.10, p = 0.82). In CAM, there were no significant time x group interactions in the time domain: mean RR intervals (942.4 ms ± 117.5 x 947.16 ms ± 122.5, p = 0.77), SDNN (33.9 ms ± 20.1 x, 33.5 ms± 24.4 p =0.33), PNN50 (14.5% ± 18.2 x 14.6% ± 18.7, p = 0.28) and domain of frequency: LF (0.078 un ± 0.026 x 0.071 un ± 0.028, p = 0.25), HF (0.256 un ± 0.063 x 0.249 un ± 0.058, p = 0.49). significant differences in BVP and CAM in hypertensive patients.