L-arginine does not improve biochemical and hormonal response in trained runners after 4 weeks of supplementation.

摘要: It has been hypothesized that L-arginine improves exercise performance by increasing nitric oxide synthesis and levels of insulin growth hormone (GH). Metabolic hormonal responses to chronic supplementation may clarify the mechanisms underlying its putative physiologic effects on physical performance. Therefore, aim this study was investigate 4 weeks with would have metabolic parameters at rest in response exercise. Fifteen healthy runners were divided into treatment (ARG; 6 g L-arginine) placebo (PLA; cornstarch) groups. On first visit, blood samples collected for baseline, supplement or provided. After (second visit), following intervals: rest, immediately after 5-km time-trial running test (5km-TT), second 5km-TT, 20 minutes recovery (+20). In addition (total time), plasma nitrate, nitrite, nitrate plus cyclic guanosine monophosphate, lactate, ammonia serum insulin, GH, insulin-like factor 1, cortisol concentrations evaluated. There significant increases +20 both ARG PLA. Nitrate nitrite increased only +20. No change observed 1 any sample period. Total time did not differ significantly between 2 tests, either Thus, according our results, cause beneficial changes parameters, beyond those achieved alone.