1075 BENEFITS OF RESISTANCE EXERCISE TRAINING IN OVARIECTOMIZED SPONTANEOUSLY HYPERTENSIVE RATS

Abstract

Background: Hypertension is a major risk factor in the development of cardiovascular disease and increase in menopause women. Aerobic Exercise has been indicated as a nonpharmacological treatment for hypertension, however the benefits of resistance exercise are not well know. Objectives: Investigate the effects of resistance exercise on cardiovascular autonomic control in ovariectomized hypertensive rats Methodos: Female Wistar (W) and spontaneously hypertensive rats (SHR) were divided into 4 groups (n = 8 each): sedentary W (WS), sedentary SHR (HS), sedentary ovariectomized SHR (HSO) and trained ovariectomized SHR (HTO). The resistance exercise training (RT) was performed in a vertical ladder with weights attached to rat tail (8 weeks; 40-50% maximal load). Arterial pressure (AP) and heart rate (HR) were directly recorded and baroreflex sensitivity (BRS) was evaluated by bradycardic (BR) and tachycardic responses (TR). Results: The mean arterial pressure was higher in HSO (180 ± 4.5 mmHg) and HS (172 ± 3.1 mmHg) compared to HTO (158 ± 2.3 mmHg) and WS (113 ± 1.5 mmHg). The RT induced resting bradycardia (HTO: 322 ± 8.6 bpm) in relation to the other groups. The TR was lower in HS (-1.81 ± 0.06 bpm/mmHg) and HSO (-0.92 ± 0.14 bpm/mmHg) in relation to WS (-2.67 ± 0.2 bpm/mmHg), and was additionally attenuated by ovariectomy (HSO vs. HS). The hypertensive groups had lower BR when compared to WS. The HTO group (-1.42 ± 0.1 bpm/mmHg) showed higher TR in relation to HSO group. Conclusions: Moderate intensity dynamic resistance exercise training induced a reduction in blood pressure and attenuated baroreflex dysfunction in ovariectomized hypertensive rats, suggesting a positive role of this nonpharmacological approach in the management of cardiovascular risk in hypertension after hormones deprivation.