Hydrogen Inhalation Slightly Lowers Oxygen Levels in Healthy Women
- Authors
- Pavel Grepl, Jakub Krejčí, Andrew J McKune, Michal Botek
- Journal
- Canadian Journal of Physiology and Pharmacology
- Year
- 2025
- DOI
- 10.1139/cjpp-2025-0228
- Study Type
- Human
- Outcome
- Neutral
- Peer Reviewed
- Yes
- Country
- Czech Republic
- Health Condition
- Heart
- Body System
- Cardiovascular
TL;DR
Hydrogen inhalation caused a small, non-meaningful decrease in oxygen saturation but did not affect heart rate variability or autonomic nervous system function in healthy adults.
Key Finding
Sixty minutes of hydrogen gas inhalation produced a statistically significant but clinically insignificant decrease in blood oxygen saturation (95.9% vs 96.7% placebo) and did not alter heart rate variability in healthy women at rest.
Summary
Researchers tested whether breathing hydrogen gas for 60 minutes would affect blood oxygen levels and heart rhythm regulation in 20 healthy young women. They found that hydrogen inhalation caused a small drop in blood oxygen saturation (95.9% versus 96.7% with placebo), but this difference was too small to matter clinically. Heart rate variability—a measure of how well the heart's nervous system adapts—showed no changes with hydrogen compared to placebo.
Practical Takeaway
This small study in healthy young women suggests that breathing hydrogen gas for an hour does not meaningfully affect oxygen levels or heart regulation at rest. However, the findings are limited to resting conditions in a specific population, and more research is needed to understand hydrogen's effects during activity or in other groups.
Abstract
Molecular hydrogen has gained attention for its potential antioxidant, anti-inflammatory, and ergogenic effects. However, its impact on blood oxygen saturation and autonomic cardiac regulation under resting conditions remains unclear. This randomized, double-blind, placebo-controlled crossover study investigated the effects of a 60-minute molecular hydrogen inhalation on oxygen saturation and heart rate variability in healthy females. Twenty physically active participants (22.1 ± 1.6 years) completed two inhalation sessions with either molecular hydrogen or placebo (ambient air), separated by a seven-day washout period. Oxygen saturation and heart rate variability were continuously monitored during the 60 minutes of inhalation. The results using 60-minute averages showed a statistically significant (p ≤ 0.007) decrease in oxygen saturation during molecular hydrogen inhalation (95.9 ± 1.0%) compared to placebo (96.7 ± 0.7%), but this decrease should not be considered clinically significant. No significant changes (all p ≥ 0.32) were observed in time-domain or frequency-domain heart rate variability indices. These findings suggest that, under resting conditions, molecular hydrogen inhalation does not induce functional changes in autonomic cardiac regulation, and the observed reduction in blood oxygen saturation does not compromise homeostatic stability.