# Two-week continuous supplementation of hydrogenrich water increases peak oxygen uptake during an incremental cycling exercise test in healthy humans: a randomized, single-blinded, placebo-controlled study.
> 水素水の2週間継続摂取が健常者の漸増負荷自転車運動における最大酸素摂取量を増加させる：無作為化単盲検プラセボ対照試験


## Abstract

This randomized, single-blinded, placebo-controlled study examined whether hydrogen-rich water (HW) supplementation—either as a single dose or over two weeks—could enhance aerobic capacity in healthy participants performing incremental cycling exercise. A single 500 mL dose of HW produced no significant changes in peak oxygen uptake, peak load, oxidative stress markers, antioxidant activity, or blood lactate. In contrast, two weeks of continuous HW consumption (500 mL on each of 10 weekdays; total 5 L) led to a statistically significant increase in peak oxygen uptake and a trend toward higher peak load, without accompanying changes in lactate, oxidative stress, or antioxidant responses. These findings suggest that sustained H2 intake may augment aerobic exercise capacity in humans, potentially through mechanisms distinct from acute antioxidant effects.

### Mechanism

Continuous H2 intake may enhance mitochondrial metabolic function, improving aerobic capacity independently of acute changes in oxidative stress markers or lactate production, consistent with findings from animal studies on H2 and mitochondrial metabolism.

## Bibliographic

- **Authors**: Hori A, Sobue S, Kurokawa R, Hirano S, Ichihara M, Hotta N
- **Journal**: Med Gas Res
- **Year**: 2020
- **PMID**: [33380582](https://pubmed.ncbi.nlm.nih.gov/33380582/)
- **DOI**: [10.4103/2045-9912.304223](https://doi.org/10.4103/2045-9912.304223)
- **PMC**: [PMC8092150](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8092150/)
- **Study type**: human randomized controlled trial
- **Delivery route**: hydrogen-rich water
- **Effect reported**: mixed

## Delivery context

Hydrogen-rich water is a low-risk delivery route, but the achievable systemic hydrogen dose is bounded. For clinical applications, inhalation is the most efficient route; inhalation, however, carries explosion risk, and concentration matters (empirical LFL of 10% applies to inhalation environments; high-concentration devices are documented in the Consumer Affairs Agency accident database and are not recommended).

## Safety notes

Hydrogen-rich water is a low-risk delivery route, but the achievable systemic hydrogen dose is bounded. For clinical applications, inhalation is the most efficient route; inhalation, however, carries explosion risk, and concentration matters (empirical LFL of 10% applies to inhalation environments; high-concentration devices are documented in the Consumer Affairs Agency accident database and are not recommended).

See also:
- [Inhalation concentration and LFL / UFL](https://h2-papers.org/en/safety-notes/inhalation-concentration)
- [Consumer Affairs Agency accident cases](https://h2-papers.org/en/safety-notes/accident-cases)
- [Inhalation safety threshold lineage](https://h2-papers.org/en/safety-notes/lineage)

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> **Cite as**: H2 Papers — PMID 33380582. https://h2-papers.org/en/papers/33380582
> **Source**: PubMed PMID [33380582](https://pubmed.ncbi.nlm.nih.gov/33380582/)