Pre-Exercise Ingestion of Hydrogen-Rich Cold Water Enhances Endurance Performance and Lactate Response in Heat
Khlifi M, Jebabli N, Ouerghi N, Yagin FH, Dutta AK, Alwhaibi R, Bouassida A. · Medicina (Kaunas). 2025;61(7):1173.
Study at a glance
Human
Healthy male sports-science students accustomed to exercising in the heat.
Participants drank 500 mL hydrogen-rich cold water 30 minutes before a 20-m shuttle-run test in a hot indoor environment. · Manufacturer-reported dissolved H₂ concentration 1,600 ppb after three minutes of electrolysis; water temperature 1–3°C and oxidation-reduction potential −650 mV. The study did not independently verify the H₂ concentration.
Single drink 30 minutes before each shuttle-run visit.
Maximal aerobic speed and shuttle repetitions favored H₂-rich cold water versus cold-water control. Dehydration, lactate, perceived exertion and feeling scale favored both H₂ water and external precooling versus control, with no significant H₂-versus-external-precooling differences for several of these outcomes. Mean and peak heart rate were null. The body-temperature analysis contained a significant pretest difference and the clearest contrast was external precooling versus control.
Small young-male study; the H₂ condition also used very cold water, the H₂ concentration came from the manufacturer, no room-temperature H₂-water arm separated hydrogen from cooling, dose was not normalized by body mass and many outcomes were compared. Princess Nourah bint Abdulrahman University support and AlMaarefa University acknowledgement were reported; authors declared no conflicts.
What kind of evidence is this?
Human
Double-blind counterbalanced crossover trial
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
Healthy male sports-science students accustomed to exercising in the heat.
22 men; mean age 19.32±0.84 years. All participants completed all three conditions.
Single drink 30 minutes before each shuttle-run visit.
Participants drank 500 mL hydrogen-rich cold water 30 minutes before a 20-m shuttle-run test in a hot indoor environment.
H₂ dissolved in cold water — not inhaled gas and not Brown's gas.
Manufacturer-reported dissolved H₂ concentration 1,600 ppb after three minutes of electrolysis; water temperature 1–3°C and oxidation-reduction potential −650 mV. The study did not independently verify the H₂ concentration.
The same 500 mL cold mineral water without H₂, plus a third condition combining cold water with external lower-limb ice-pack precooling; one-week washouts separated visits.
Outcomes and reported result
Maximal aerobic speed, shuttle repetitions, dehydration, measured body temperature, heart rate, post-exercise lactate, perceived exertion and feeling scale.
Maximal aerobic speed and shuttle repetitions favored H₂-rich cold water versus cold-water control. Dehydration, lactate, perceived exertion and feeling scale favored both H₂ water and external precooling versus control, with no significant H₂-versus-external-precooling differences for several of these outcomes. Mean and peak heart rate were null. The body-temperature analysis contained a significant pretest difference and the clearest contrast was external precooling versus control.
The complete MDPI/PMC article, crossover protocol, water preparation, every outcome table and figure, null heart-rate results, funding and conflict disclosure were checked.
A reported association, difference or mechanism is not automatically a clinical benefit.
Limitations and applicability
Small young-male study; the H₂ condition also used very cold water, the H₂ concentration came from the manufacturer, no room-temperature H₂-water arm separated hydrogen from cooling, dose was not normalized by body mass and many outcomes were compared. Princess Nourah bint Abdulrahman University support and AlMaarefa University acknowledgement were reported; authors declared no conflicts.
Young heat-acclimatized men performing one laboratory shuttle-run protocol; not evidence for clinical treatment or long-term training benefit.
No single-study GRADE certainty rating is assigned. Read how records and evidence assessments are prepared.
Sources and record status
PMID: 40731803 · DOI: 10.3390/medicina61071173
Open-access full article on MDPI and PubMed Central.
MDPI XML/full article, PMC full article and PubMed metadata; full-text and article-status check completed 8 August 2026.
10 August 2026
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