Application of Molecular Hydrogen as an Antioxidant in Responses to Ventilatory and Ergogenic Adjustments during Incremental Exercise in Humans

We investigated effects of molecular hydrogen (H-2) supplementation on acid-base status, pulmonary gas exchange responses, and local muscle oxygenation during incremental exercise. Eighteen healthy, trained subjects in a randomized, double-blind, crossover design received H-2-rich calcium powder (HCP) (1500 mg/day, containing 2.544 mu g/day of H-2) or H-2-depleted placebo (1500 mg/day) for three consecutive days. They performed cycling incremental exercise starting at 20-watt work rate, increasing by 20 watts/2 min until exhaustion. Breath-by-breath pulmonary ventilation ((V)over dot(E)) and CO2 output ((V)over dotCO(2)) were measured and muscle deoxygenation (deoxy[Hb + Mb]) was determined via time-resolved near-infrared spectroscopy in the vastus lateralis (VL) and rectus femoris (RF). Blood gases' pH, lactate, and bicarbonate (HCO3-) concentrations were measured at rest and 120-, 200-, and 240-watt work rates. At rest, the HCP group had significantly lower (V)over dot(E), (V)over dotCO(2), and higher HCO3-, partial pressures of CO2 (PCO2) versus placebo. During exercise, a significant pH decrease and greater HCO3- continued until 240-watt workload in HCP. The (V)overdot(E) was significantly lower in HCP versus placebo, but HCP did not affect the gas exchange status of (V)over dotCO(2) or oxygen uptake ((V)over dotO(2)). HCP increased absolute values of deoxy[Hb + Mb] at the RF but not VL. Thus, HCP-induced hypoventilation would lead to lower pH and secondarily impaired balance between O-2 delivery and utilization in the local RF during exercise, suggesting that HCP supplementation, which increases the at-rest antioxidant potential, affects the lower ventilation and pH status during incremental exercise. HPC induced a significantly lower O-2 delivery/utilization ratio in the RF but not the VL, which may be because these regions possess inherently different vascular/metabolic control properties, perhaps related to fiber-type composition.

Automated summary

The study showed that supplementation with HCP led to decreased muscle oxygenation, impacting the pH levels and balance between oxygen delivery and utilization during exercise.