L-arginine increases endothelial nitric oxide production and reduces blood pressure of rest without changing the exercise pressor response

Abstract

L-arginine supplementation has been proposed to improve endothelial. The hypothesis that L-arginine also improves post-exercise hypotension (PEH) in hypertensive individuals was tested in this study. Physically active hypertensive women were divided into supplemented (SUP) (n = 12, 50 ± 1.8 years) and placebo (PLA) (n = 14, 51.5 ± 1.6 years) groups performing two walking sessions at moderate intensity with interval of 32 days between sessions. Blood samples were collected and blood pressure (BP) was measured before and after exercise. In the period between sessions, they remained physically active and received daily 6g of L-arginine or placebo. PLA showed no change in serum nitrite/nitrate concentration and blood pressure at rest or in response to exercise. SUP showed increased basal nitrite/nitrate plasma concentration (26.6 ± 2 to 44.6 ± 4µM, p < .05), which was followed by reduction of basal BP (137/86.2 to 125.8/79mmHg, p < .05). The exercise performed before supplementation did not change the serum nitrite/nitrate concentration. After supplementation, the exercise promoted increases in levels from 44.6 ± 4 to 51.8 ± 6µM (p < .05). However, it did not change the PEH. L-arginine supplementation improves the nitrite/nitrate production and decreases the resting BP, but does not change the PEH in hypertensive middle-aged women.