Acute Effects of Molecular Hydrogen Inhalation on Exercise-Induced Oxidative Stress, Vascular Responses, and Performance in National-Level Female Rowers: An Exploratory Pilot Case Series
Harada Y, Kibe M, Miyakawa M · 2026
Research-use notice
Independent study record
Each H2HUBB study page organizes source-linked research details for educational use. Interpretation should remain proportional to the study design, population, controls, and limitations.
H2HUBB TAKEAWAY
In 3 participants, during recovery, urinary 8-OH-dG tended to be lower under H₂ (HL-9.9; exact p=0.25), suggesting a potential attenuation of oxidative DNA damage, and venous diameter also showed consistent differences (HL-2.88 mm; exact p=0.125). These findings add human evidence supporting molecular hydrogen's therapeutic potential to influence oxidative-stress regulation.
What the Findings Mean
H2HUBB reviewed how molecular hydrogen affected the outcomes measured in 3 participants. During recovery, urinary 8-OH-dG tended to be lower under H₂ (HL-9.9; exact p=0.25), suggesting a potential attenuation of oxidative DNA damage, and venous diameter also showed consistent differences (HL-2.88 mm; exact p=0.125).
What the Researchers Studied
The researchers studied 3 participants. The comparison condition was placebo.
What Effects Did Molecular Hydrogen Have?
Source-reported hydrogen concentration: 4% source-reported H₂ gas concentration; Source-reported hydrogen exposure: 4% source-reported H₂ gas concentration. During recovery, urinary 8-OH-dG tended to be lower under H₂ (HL-9.9; exact p=0.25), suggesting a potential attenuation of oxidative DNA damage, and venous diameter also showed consistent differences (HL-2.88 mm; exact p=0.125). The authors concluded that in this feasibility-constrained, fixed-order pilot case series (n=4), hydrogen inhalation showed directionally favorable signals in selected biochemical, vascular, and performance indices, but efficacy cannot be inferred because learning, fatigue, and carry-over effects cannot be separated. Evidence for the acute effects of molecular hydrogen (H₂) inhalation on exerciserelated responses remains limited, particularly in elite female athletes exposed to high oxidative stress during intense exercise.
Why These Findings Matter
These findings add human evidence supporting molecular hydrogen's therapeutic potential to influence oxidative-stress regulation and contribute to the growing body of molecular-hydrogen research.
How Strong Is This Evidence?
This is human clinical evidence from a case report. 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 case report with human clinical evidence. The research population or model was 3 participants. The source-reported hydrogen concentration was 4% source-reported H₂ gas concentration.
Limitations and Safety
No separate limitations or safety findings were identified in the 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. The original scholarly source is available at https://europepmc.org/article/PPR/PPR1199830.