Low intensity resistance training increases spontaneous baroreflex sensitivity

Physical exercise is an adjuvant treatment to control and prevent cardiovascular dysfunction which results in the reduction of the occurrence of complications and mortality. A reduction in baroreflex sensitivity is related to autonomic dysfunction and increases mortality risk in cardiac patients. Therefore we aimed to evaluate changes in baroreflex function in response to low intensity resistance training in rats. The animals were enrolled in the trained group (TG, n=5) or sedentary group (SG, n=5). The exercise was performed on a squat-training apparatus using 3×10 repetitions, 3 times a week for 8 weeks. The SG was placed on the squat-training apparatus but performed no exercise. After measurement of the maximum weight lifted (1RM), the training load was set at 40% of 1RM and adjusted every 15 days. At the end of the training protocol or time control, the animals were anesthetized with thiopental (50 mg/kg i.p.) and are instrumentated to record blood pressure (BP) and analyze spontaneous baroreflex sensitivity (BRS). There was a decrease in the heart rate (TG=365.4±7.796; SG=405.0±4.492; p=0.0023) and increase in BRS (TG=0.8809±0.01026; SG=0.8088±0.01882; p=0.0099) in trained animals when compared to sedentary, without changes in blood pressure between groups. The low intensity resistance training was able to promote an increase in spontaneous baroreflex sensitivity and therefore bradycardia in trained animals.