Neurohumoral and Endothelial Responses to Heated Water-Based Exercise in Resistant Hypertensive Patients

Abstract

Background: The neurohumoral and endothelial responses to the blood pressure (BP) lowering effects of heated water- based exercise (HEx) in resistant hypertension (HT) patients remain undefined. Methods and Results: We investigated these in 44 true resistant HT patients (age 53.3 +/- 0.9 years, mean +/- SEM). They were randomized and allocated to 2 groups, 28 to a HEx training protocol, which consisted of callisthenic exercises and walking in a heated pool for 1 h, three times weekly for 12 weeks and 16 patients to a control group maintaining their habitual activities. Measurements made before and after 12 weeks of HEx included clinic and 24-h BP, plasma levels of nitric oxide, endothelin- 1, aldosterone, renin, norepinephrine and epinephrine, as well as peak V. O2, and endothelial function (reactive hyperemia). After 12 weeks of HEx patients showed a significant decrease in clinic and 24- h systolic and diastolic BPs. Concomitantly, nitric oxide increased significantly (from 25 +/- 8 to 75 +/- 24 mu mol/ L, P < 0.01), while endothelin-1 (from 41 +/- 5 to 26 +/- 3 pg/ mL), renin (from 35 +/- 4 to 3.4 +/- 1 ng/mL/h), and norepinephrine (from 720 +/- 54 to 306 +/- 35 pg/ mL) decreased significantly (P < 0.01). Plasma aldosterone also tended to decrease, although not significantly (from 101 +/- 9 to 76 +/- 4 pg/ mL, P=NS). Peak VO2 increased significantly after HEx (P < 0.01), while endothelial function was unchanged. No significant change was detected in the control group. Conclusions: The BP-lowering effects of HEx in resistant HT patients were accompanied by a significant reduction in the marked neurohumoral activation characterizing this clinical condition.