Inhaling or ingesting hydrogen (H2) gas improves oxidative stress-induced damage in animal models and humans. It has been previously reported that H2 was consumed throughout the human body after the ingestion of H2-rich water and that the H2 consumption rate (VH2) was 1.0 μmol/min/m(2) body surface area. To confirm this result, authors evaluated VH2 during the inhalation of low levels of H2 gas. After measuring the baseline levels of exhaled H2 during room air breathing via a one-way valve and a mouthpiece, the subject breathed low levels (160 ppm) of H2 gas mixed with purified artificial air. The H2 levels of their inspired and expired breath were measured by gas chromatography using a semiconductor sensor. VH2 was calculated using a ventilation equation derived from the inspired and expired concentrations of O2/CO2/H2, and the expired minute ventilation volume, which was measured with a respiromonitor. As a result, VH2 was found to be approximately 0.7 μmol/min/m(2)BSA, which was compatible with the findings authors obtained using H2-rich water. VH2 varied markedly when pretreatment fasting to reduce colonic fermentation was not employed, i.e., when the subject’s baseline breath hydrogen level was 10 ppm or greater. Reported H2 inhalation method might be useful for the noninvasive monitoring of hydroxyl radical production in the human body.
Shimouchi A, Nose K, Mizukami T, Che DC, Shirai M. Molecular hydrogen consumption in the human body during the inhalation of hydrogen gas. Adv Exp Med Biol. 2013;789:315-21.