Sixty-minute inhalation of molecular hydrogen decreases blood oxygen saturation but does not alter autonomic cardiac regulation at rest in healthy females: a randomized, double-blind, placebo-controlled crossover study.
Pavel Grepl, Jakub Krejčí, Andrew McKune, Michal Botek · Canadian journal of physiology and pharmacology · 2026
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Independent study record
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H2HUBB TAKEAWAY
The results using 60 min 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. These findings add human evidence supporting molecular hydrogen's therapeutic potential to influence cardiac autonomic regulation in healthy women.
What the Findings Mean
H2HUBB reviewed how molecular hydrogen affected the outcomes measured in 20 physically active participants. The results using 60 min 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.
What the Researchers Studied
The researchers studied 20 physically active participants. The study used a randomized, double-blind, placebo-controlled, crossover human clinical trial. The comparison condition was placebo.
What Effects Did Molecular Hydrogen Have?
This randomized, double-blind, placebo-controlled crossover study investigated the effects of a 60 min molecular hydrogen inhalation on oxygen saturation and heart rate variability in healthy females. The results using 60 min 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. The authors concluded that 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.
Why These Findings Matter
These findings add human evidence supporting molecular hydrogen's therapeutic potential to influence cardiac autonomic regulation in healthy women and contribute to the growing body of molecular-hydrogen research.
How Strong Is This Evidence?
This is human clinical evidence from a randomized, double-blind, placebo-controlled, crossover human clinical trial. H2HUBB interprets the findings in the context of the study design, sample, comparator, and measured outcomes rather than using one publication as a verdict on hydrogen therapy.
Technical Study Details
H2HUBB classifies this publication as human clinical study with human clinical evidence. The research population or model was 20 physically active participants. The study used a randomized, double-blind, placebo-controlled, crossover human clinical trial.
Limitations and Safety
No separate limitations or safety findings were identified in the current-study source text available to H2HUBB.
Original Study and H2HUBB Research Context
H2HUBB presents this source-grounded research record as one contribution to the broader molecular-hydrogen evidence base.