Effect of Treadmill Exercise and Hydrogen-rich Water Intake on Serum Oxidative and Anti-oxidative Metabolites in Serum of Thoroughbred Horses.
Tsubone H, Hanafusa M, Endo M, Manabe N, Hiraga A, Ohmura H, Aida H. · Journal of Equine Science. 2013;24:1-8.
What kind of evidence is this?
Preclinical
Non-randomized crossover horse study
Exercise and recovery
H₂-rich water
Mostly neutral or mixed preclinical signal.
Animal exercise biomarker outcomes.
Methods at a glance
Trained Thoroughbred horses completing treadmill exercise.
Four horses completed placebo and hydrogen-water trials.
Two exercise trials separated by one week.
2 L hydrogen-rich water by nasogastric catheter 30 minutes before treadmill exercise.
H2 dissolved in water; not Brown's gas.
More than 1 ppm dissolved H2 at administration.
Not applicable — nasogastric water.
No oxygen was co-delivered.
Placebo water, always tested before hydrogen-rich water.
Outcomes and reported result
Serum oxidative and antioxidant metabolites before and after treadmill exercise.
A between-condition difference was reported for one antioxidant/oxidative ratio, but interaction testing and most measures did not show a clear hydrogen-water effect.
The full article, trial order, figures and significant and null findings were checked.
A reported association, difference or mechanism is not automatically a clinical benefit. Null findings, outcome type, study design and precision all matter.
Cautions and applicability
Only four horses and fixed treatment order create major carryover and period-bias concerns.
Trained Thoroughbred horses under the reported treadmill protocol.
SYRCLE animal-study tool — preliminary
Some concerns
No randomized treatment order, extremely small sample and unclear blinding.
Randomization/allocation reporting is limited · Blinding of personnel is unclear · Attrition is incompletely reported in places · Blinding of outcome assessors is unclear · No prospectively registered analysis plan identified
No single-study GRADE certainty rating is assigned. Certainty is assessed by important outcome across a complete eligible evidence set, not by attaching a final grade to one source.
Sources and record status
PMID: 24833996 · DOI: 10.1294/jes.24.1
Free full article in PubMed Central.
PubMed record and PubMed Central full text; extraction checked 9 August 2026.
2026-08-10