Hydrogen gas inhalation prior to high-intensity training reduces attenuation of nitric oxide bioavailability in male rugby players.

Background: Inhalation of hydrogen gas (H₂) 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 H₂ 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 H₂ 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 H₂ 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 H₂ inhalation week than in the placebo week on D6 and D7. In addition, total antioxidant levels were significantly higher with H₂ inhalation than with placebo.

Significance: These results suggest that H₂ inhalation helps to maintain NO signaling after exercise and to alleviate inflammation and oxidative stress induced by high-intensity exercise training in professional athletes.