Molecular hydrogen downregulates acute exhaustive exercise-induced skeletal muscle damage
Nogueira JE, Amorim MR, Pinto AP, da Rocha AL, da Silva ASR, Branco LGS. · Can J Physiol Pharmacol. 2021;99(8):812–820.
What kind of evidence is this?
Preclinical
Randomized controlled rat study
Exercise and recovery
Inhaled H₂
Mixed biomarker signal; performance null.
Performance and muscle biomarker outcomes in rats.
Methods at a glance
Male Wistar rats assigned to sedentary or acute exhaustive exercise conditions.
Four groups; analyzed group counts vary by assay and were not consolidated beyond the reported range.
Acute session.
2% H₂ inhalation before and during treadmill exercise.
Inhaled H₂-containing gas.
2% H₂.
30-minute acclimation followed by the 45-minute exercise exposure.
Control-gas conditions were used.
Sedentary and exercise groups inhaling control gas.
Outcomes and reported result
Exercise performance, SOD, TBARS, glutathione and cleaved caspase-3 in skeletal muscle.
H₂ did not improve exercise performance; selected oxidative and apoptotic markers favored H₂, while several measures were null.
The full article methods, intervention, outcomes, positive and null findings, funding and conflict statements 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
Acute animal study with small and variably reported assay samples.
The reported acute-exercise rat model only.
SYRCLE animal-study tool — preliminary
Some concerns
Randomization was reported, but group-size reporting, concealment and assessor blinding were limited.
Sequence generation checked where reported · Allocation concealment generally unclear · Personnel blinding generally unclear · Outcome-assessor blinding generally 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: 33356867 · DOI: 10.1139/cjpp-2020-0297
A free publisher or repository full article was checked.
Publisher or repository full article and bibliographic record; checked 10 August 2026.
2026-08-10