Effects of 7-day intake of hydrogen-rich water on physical performance of trained and untrained subjects
Timón R et al. · Biol Sport. 2021;38(2):269–275.
Study at a glance
Human
Trained amateur cyclists and untrained adults
Nano-bubble hydrogen-rich water, 1,920–2,240 mL/day (six or seven 320 mL bottles), consumed immediately after each hydrogenation cycle · 1.9 ppm dissolved H₂; pH 7.5 and oxidation-reduction potential −600 mV reported.
7 days per condition in a crossover design
Only the trained cyclists showed higher anaerobic peak and mean power and a lower fatigue index after H₂ water. Untrained participants did not show these changes. Aerobic performance did not improve; trained cyclists had lower lactate after the aerobic test.
Small crossover subgroups and several outcomes. The authors reported no conflicts; a company lent the portable bottles and public regional funding supported the study.
What kind of evidence is this?
Human
Randomized double-blind placebo-controlled crossover study
Exercise and recovery
H₂-rich water
Information not yet classified
Some editorial classification fields are still pending. The source-reported outcomes and result are shown below; Hydrogenology does not infer a positive or negative signal from prose automatically.
Methods
Trained amateur cyclists and untrained adults
37 recruited; analyzed groups reported as 12 trained cyclists and 15 untrained participants
7 days per condition in a crossover design
Nano-bubble hydrogen-rich water, 1,920–2,240 mL/day (six or seven 320 mL bottles), consumed immediately after each hydrogenation cycle
H₂ dissolved in water — H₂ only, not Brown’s gas.
1.9 ppm dissolved H₂; pH 7.5 and oxidation-reduction potential −600 mV reported.
Placebo purified water produced and consumed with the same portable-bottle procedure
Outcomes and reported result
Incremental peak-oxygen-uptake test, maximal anaerobic cycling test, power, fatigue index, lactate and perceived exertion
Only the trained cyclists showed higher anaerobic peak and mean power and a lower fatigue index after H₂ water. Untrained participants did not show these changes. Aerobic performance did not improve; trained cyclists had lower lactate after the aerobic test.
Dose, methods, full results, funding and conflict statement checked in the open-access full text; independent appraisal remains incomplete.
A reported association, difference or mechanism is not automatically a clinical benefit.
Limitations and applicability
Small crossover subgroups and several outcomes. The authors reported no conflicts; a company lent the portable bottles and public regional funding supported the study.
Trained amateur cyclists and untrained adults under the reported short intervention and laboratory tests.
No single-study GRADE certainty rating is assigned. Read how records and evidence assessments are prepared.
Sources and record status
PMID: 34079172 · DOI: 10.5114/biolsport.2020.98625
Open-access full text is available through PMC.
Open-access PMC full text and PubMed bibliographic record.
10 August 2026
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