Decompression Comparison of Helium and Hydrogen in Rats
Decompression comparison of helium and hydrogen in rats
Research hubs: Respiratory System · Brain & Nervous System
This research was done in animals. Results in animals often don't carry over to people.
- Evidence type
- Animal study (rat)
- Authors
- R. S. Lillo, E. C. Parker, W. R. Porter
- Journal
- Journal of Applied Physiology
- Year
- 1997
- PMID
- 9074979
- Study Type
- Rat
- Participants
- 1607
- Delivery
- Gas
- Dose
- 2% O2-balance H2, depths ≤50 ATA, bottom times ≤60 min, decompression to 10.8 ATA with varying profiles and up to four decompression stops of up to 60 min each
- H₂ concentration
- 2% H2 gas
- Outcome
- Neutral
- Peer Reviewed
- Yes
- Cited by
- 25 (OpenAlex, as of November 2026)
- Country
- United States
TL;DR
Hydrogen gas may pose a higher risk of decompression sickness than helium gas in rats, despite being eliminated from the body faster.
Key Finding
Hydrogen gas showed 35% greater potency for causing decompression sickness in rats compared to helium, though hydrogen was eliminated from the body significantly faster.
Summary
Researchers compared how dangerous decompression (rapid pressure changes) is when divers breathe hydrogen versus helium by studying 1,607 rats. They found that hydrogen was 35% more likely to cause decompression sickness (a painful condition from pressure changes), but hydrogen also left the body much faster than helium. The study authors noted it's unclear whether these rat findings would apply to human divers.
Practical Takeaway
This is a rat study examining diving physiology, not hydrogen water for health. The findings are too preliminary and animal-specific to inform consumer decisions about hydrogen water. The study does not address hydrogen water consumption or its effects on human health.
Abstract (excerpt)
Lillo, R. S., E. C. Parker, and W. R. Porter.Decompression comparison of helium and hydrogen in rats. J. Appl. Physiol. 82(3): 892–901, 1997.—The hypothesis that there are differences in decompression risk between He and H2 was examined in 1,607 unanesthetized male albino rats subjected to dives…