Effect of L-arginine intake on exercise-induced hypotension.

Objective: to verify if one single dose of L-arginine improves post-exercise hypotension (PEH) in hypertensive. Methods: double-blind, placebo, randomized with 20 hypertensive (51.47 +/- 1.24 years). Two sessions of aerobic exercise were performed proceeded for the ingestion of one dose of 7 g of L-arginine (EX-LARG) or placebo (EX-PLA), plus one session only with L-arginine ingestion (L-ARG). Blood pressure (BP) was measured at rest, and each ten minutes for a period of 60 minutes recovery after exercise. Blood samples were taken before and after exercise for analysis of plasma concentration of nitrite and malondialdehyde (MDA). One-way ANOVA tests were used to compare the baseline conditions and two-way ANOVA, to evaluate possible differences in pressure responses between procedures. Results: both sessions EX-LARG and EX-PLA showed similar peak reduction for the mean systolic blood pressure (-6.58 +/- 0.95 mmHg and -8.38 +/- 1.29 mmHg respectively, p = 0.28). On the other hand, for the diastolic component, only L-ARG was able to promote PEH (-1.85 +/- 0.44 mmHg), significantly better than EX-PLA (+2.13 +/- 0.62 mmHg; p < 0.01). L-ARG alone did not result in significant changes in BP. Nitrite and MDA behaved similarly between procedures. Conclusion: a single dose of L-arginine before exercise improves diastolic PEH.