Abstract
BACKGROUND: Inhalation of hydrogen gas (H(2)) as an antioxidant supplement may alleviate exercise-induced oxidative damage and protect post-exercise hydrogen peroxide signaling, which may help mediate beneficial exercise adaptation. The aims of this study were to determine the effects of H(2) inhalation on plasma nitric oxide (NO) level and its synthesis precursor in professional athletes. METHODS: A randomized, placebo-controlled, double-blind, crossover trial was conducted with professional male rugby players for 3 weeks. Participants underwent 1 week of H(2) supplementation and 1 week of placebo treatment prior to daily sessions of high-intensity exercise training, separated by 1 week of low-intensity training as a washout. RESULTS: Two-way (supplementation and time) repeated-measures analyses of variance showed that NO, L-arginine, and tetrahydrobiopterin levels in the H(2) inhalation group were significantly higher than those in the placebo group after exercise (D6) and remained higher after 24 h of rest (D7). Levels of hydroxydeoxyguanosine and interleukin 6 were lower in the H(2) inhalation week than in the placebo week on D6 and D7. In addition, total antioxidant levels were significantly higher with H(2) inhalation than with placebo. SIGNIFICANCE: These results suggest that H(2) inhalation helps to maintain NO signaling after exercise and to alleviate inflammation and oxidative stress induced by high-intensity exercise training in professional athletes.