Effects of molecular hydrogen supplementation on fatigue and aerobic capacity in healthy adults: A systematic review and meta-analysis

Abstract

BackgroundFatigue is oftentimes induced by high-intensity exercise potentially via the exceeded amount of reactive oxygen species, leading to diminished functions (e.g., aerobic capacity) and increased risk of injuries. Studies indicate that molecular hydrogen (H2), with antioxidant and anti-inflammatory properties, may be a promising strategy to alleviate fatigue and improve aerobic capacity. However, such effects have not been comprehensively characterized.ObjectiveTo systematically assess the effects of in taking H2 on fatigue and aerobic capacity in healthy adults.MethodsThe search was conducted in August 2022 in five databases. Studies with randomized controlled or crossover designs that investigated the rating of perceived exertion (RPE), maximal oxygen uptake (VO2max), peak oxygen uptake (VO2peak), and endurance performance were selected. The data (mean ± standard deviation and sample size) were extracted from the included studies and were converted into the standardized mean difference (SMD). Random-effects meta-analyses were performed. Subgroup analysis was used to analyze potential sources of heterogeneity due to intervention period, training status, and type of exercise.ResultsSeventeen publications (19 studies) consisting of 402 participants were included. The pooled effect sizes of H2 on RPE (SMDpooled = −0.38, 95%CI −0.65 to −0.11, p = 0.006, I2 = 33.6%, p = 0.149) and blood lactate (SMDpooled = −0.42, 95% CI −0.72 to −0.12, p = 0.006, I2 = 35.6%, p = 0.114) were small yet significant with low heterogeneity. The pooled effect sizes of H2 on VO2max and VO2peak (SMDpooled = 0.09, 95% CI −0.10 to 0.29, p = 0.333, I2 = 0%, p = 0.998) and endurance performance (SMDpooled = 0.01, 95% CI −0.23 to 0.25, p = 0.946, I2 = 0%, p > 0.999) were not significant and trivial without heterogeneity. Subgroup analysis revealed that the effects of H2 on fatigue were impacted significantly by the training status (i.e., untrained and trained), period of H2 implementation, and exercise types (i.e., continuous and intermittent exercises).ConclusionsThis meta-analysis provides moderate evidence that H2 supplementation alleviates fatigue but does not enhance aerobic capacity in healthy adults.Systematic review registrationwww.crd.york.ac.uk/PROSPERO/, identifier: CRD42022351559.

Can molecular hydrogen supplementation reduce exercise-induced oxidative stress in healthy adults? A systematic review and meta-analysis

“…In a recent meta-analysis, Zhou et al, observed differences in the alleviation of exercise-induced fatigue by hydrogen across different training levels and types of exercise. Taken together, such benefits of H 2 may be associated with its antioxidative capacity ( 40 ), which, however, was not explicitly examined. Recent research efforts have been put to explore the effects of H 2 on oxidative stress in humans ( 23 , 37 ).…”

Therapeutic Potential of Hydrogen-Rich Water on Muscle Atrophy Caused by Immobilization in a Mouse Model

“…However, the effects of molecular hydrogen on muscle tissue have not been extensively evaluated. Several studies indirectly asses this by evaluating the effects of molecular hydrogen on exercise performance, which clinical studies have demonstrated reduced lactate production [25] and levels of fatigue [26]. Animal studies demonstrate that H 2 treatment attenuated the exercise-induced increases in skeletal muscle TNF-α, NF-κB, IL-6, and caspase-3 levels while increasing superoxide dismutase levels [20].…”

Effects of endurance exercise on physiologic complexity of the hemodynamics in prefrontal cortex

“…Additionally, it has been shown that intaking hydrogen ( ), an antioxidant, holds great promise for helping to alleviate exercise-induced fatigue. 28 , 29 We previously observed that such effects of on fatigue are associated with its effects on the maintenance of PFC activation during the endurance exercise. Still, the effects of on the multiscale regulation of PFC hemodynamics, which can be assessed using fNIRS complexity, are unclear.…”

“…However, the effects of different physical loads of endurance exercise on the fNIRS complexity of PFC, as well as the relationship between exercise-induced changes in fNIRS complexity and that of the underlying physiologic characteristics pertaining to fatigue (e.g., HR), have not been explicitly explored. Additionally, it has been shown that intaking hydrogen (normalH2), an antioxidant, holds great promise for helping to alleviate exercise-induced fatigue 28 , 29 . We previously observed that such effects of normalH2 on fatigue are associated with its effects on the maintenance of PFC activation during the endurance exercise.…”