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

Abstract

We investigated effects of molecular hydrogen (H2) 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 H2-rich calcium powder (HCP) (1500 mg/day, containing 2.544 µg/day of H2) or H2-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˙E) and CO2 output (V˙CO2) 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˙E, V˙CO2, 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˙E was significantly lower in HCP versus placebo, but HCP did not affect the gas exchange status of V˙CO2 or oxygen uptake (V˙O2). 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 O2 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 O2 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.

The Acute Effects of a Single Dose of Molecular Hydrogen Supplements on Responses to Ergogenic Adjustments during High-Intensity Intermittent Exercise in Humans

“…The results of analyses showed that this dose of HCP significantly increased PCO 2 and HCO 3 − and showed a slight tendency toward acidosis at rest (i.e., a slightly but not significantly lowered pH). In the HCP group, the increased HCO 3 − was also reflected in the significantly increased BE, and the tendency toward acidosis in pH as a result of the increased PCO 2 could be additionally augmented as an effect of HCP’s antioxidant properties and the suppression of reactive oxygen species (ROS), as a reduced ventilatory sensitivity to hypercapnia following antioxidant administration has been observed in several studies [ 7 , 24 , 25 ]. However, further examination of the direct effect of HCP on ROS is needed.…”

“…Following our previous study’s protocol [ 7 ], the subjects were familiarized with all measurement techniques, and a familiarization test was conducted a few weeks prior to the start of the experiments; the testing sessions were separated by a 1- to 2-week washout period. All sessions were completed in Doshisha University in a custom-made environmental chamber (model LP-2.5PH-SS, NK Systems, Osaka, Japan) maintained at a temperature of 25 °C and 50% relative humidity.…”

“…The ATT was measured using a B-mode ultrasound system (Aixplorer Multiwave™, Supersonic Imagine, Aix-en-Provence, France). The tissue O 2 saturation (S t O 2 ) was calculated using oxy[Hb + Mb]/total[Hb + Mb]; for full details, see Alharbi et al [ 7 ].…”

“…Our previous study revealed that when 1500 mg of HCP was well absorbed in subjects’ intestinal tract for 3 consecutive days, it led to slight acidosis and to increases in the venous partial pressure of CO 2 (PCO 2 ) and bicarbonate ion (HCO 3 − ); in addition, the HCP significantly impacted the muscle O 2 delivery/utilization ratio in the rectus femoris ( RF ) muscles but not in the vastus lateralis ( VL ) muscles during incremental exercise, without impacting the subjects’ exercise performance [ 7 ].…”

Hydrogen, a Novel Therapeutic Molecule, Regulates Oxidative Stress, Inflammation, and Apoptosis

“…An improvement in clinical symptoms was seen in a significantly higher percentage of patients in the treatment group, who inhaled a mixture of H 2 and O 2 , than in patients in the control group, who received classic oxygen therapy, although randomization was not applied because of the urgency to deal with the outbreak (Guan et al, 2020b ). Similarly, application of H 2 improves O 2 utilization rate, reduces O 2 consumption, and improves exercise endurance as in healthy humans (Alharbi et al, 2021 ). Inhalation of the mixed gas of O 2 and H 2 can expand the bronchioles and reduce the inspiratory effort, and thus promote the absorption of O 2 by the alveoli (Zhou et al, 2019 ).…”