The Acute Effects of L-arginine on Hormonal and Metabolic Responses During Submaximal Exercise in Trained Cyclists

Abstract

L-arginine may enhance endurance performance mediated by two primary mechanisms including enhanced secretion of endogenous growth hormone (GH) and as a precursor of nitric oxide (NO); however, research in trained participants has been equivocal. The purpose was to investigate the effect of acute L-arginine ingestion on the hormonal and metabolic response during submaximal exercise in trained cyclists. Fifteen aerobically trained men (age: 28 ± 5 y; body mass: 77.4 ± 9.5 kg; height: 180.9 ± 7.9 cm; VO2max: 59.6 ± 5.9 ml·kg- 1·min-1) participated in a randomized, double-blind, crossover study. Subjects consumed L-arginine (ARG; 0. 075 g·kg-1 body mass) or a placebo (PLA) before performing an acute bout of submaximal exercise (60 min at 80% of power output achieved at ventilatory threshold). The ARG condition significantly increased plasma L-arginine concentrations (~146%), while no change was detected in the PLA condition. There were no differences between conditions for GH, nonesterified fatty acids (NEFA), lactate, glucose, VO2, VCO2, RER, CHO oxidation, and NOx. There was reduced fat oxidation at the start of exercise (ARG: 0.36 ± 0.25 vs. PLA: 0.42 ± 0.23 g·min-1, p < .05) and an elevated plasma glycerol concentrations at the 45-min time point (ARG: 340.3 vs. PLA: 288.5 μmol·L-1, p < .05) after L-arginine consumption. In conclusion, the acute ingestion of L-arginine did not alter any hormonal, metabolic, or cardio-respiratory responses during submaximal exercise except for a small but significant increase in glycerol at the 45-min time point and a reduction in fat oxidation at the start of exercise.

Oral L-Arginine Before Resistance Exercise Blunts Growth Hormone in Strength Trained Males

“…Furthermore our data does not support the auto-negative feedback loop via enhanced IGF-1 or GH since IGF-1 was not elevated from rest and GH did not rise before the exercise bout nor was there any significant difference between conditions. In addition, previous research found no effect of L-arginine supplementation on insulin at rest or plasma glucose and carbohydrate oxidation during aerobic exercise (Forbes et al, 2013).…”

Building Muscle Mass: Physiology, Nutrition, and Supplementation

“…The AAKG supplement group increased plasma L -arginine levels, but there was no difference found in NO x levels between groups. A study conducted by Forbes et al [ 161 ] assessing the effects of L -arginine supplementation among trained cyclists was mentioned previously in the growth hormone section. This study also concluded that L -arginine supplementation did not have any infl uence on NO x levels.…”

“…Another L -arginine study evaluated supplementation among trained cyclists [ 161 ]. Fifteen males were assigned to either a placebo or L -ARGININE supplement (0.075 g/kg body mass) before a submaximal exercise.…”

Tivortin Aspartate: a New Safe and Effective Non-Prohibited Medical Drug for Stimulation the Performance of Athletes

“…Одной из таких фармакологически перспектив-ных субстанций в последние годы стал L-аргинин, обладающим многогранным физиологическим дей-ствием на организм в условиях напряженной мы-шечной деятельности [25,33,34,40]. Аргинин яв-ляется незаменимой для синтеза белка в мышцах аминокислотой; прекурсором креатина, что потен-циально подразумевает наличие анаболических свойств в мышечной ткани; модулятором образо-вания эндогенного гормона роста с последующим косвенным стимулированием анаболических про-цессов; оказывает непрямое стимулирующее дей-ствие на синтез оксида азота, играет существен-ную роль в обмене адениловых нуклеотидов, что сопровождается расширением кровеносных сосу-дов, включая сосуды скелетных мышц и миокарда со снижением потребности в кислороде, ускорени-ем восстановления и замедлением развития утом-ления; является мощным кардиопротекторным средством [24,37,42,48,54].…”

“…имеют недостаточно высо-кий уровень доказательности [23]. Кроме того, аб-солютное большинство работ относительно влия-ния L-аргинина на работоспособность проведены или при разовом/курсовом применением пищевых добавок (а не лекарственных препаратов) у спорт-сменов, или в эксперименте [25,34,41,55,57].…”