Hydrogen vs Helium: Decompression Sickness Risk in Diving Study
- Authors
- R. S. Lillo, E. C. Parker, W. R. Porter
- Journal
- Journal of Applied Physiology
- Year
- 1997
- DOI
- 10.1152/jappl.1997.82.3.892
- Study Type
- Rat
- Outcome
- Neutral
- Peer Reviewed
- Yes
- Country
- United States
- Health Condition
- Decompression Sickness
- Body System
- Respiratory
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
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 on 2% O2-balance He or 2% O2-balance H2 (depths ≤ 50 ATA, bottom times ≤ 60 min). The animals were decompressed to 10.8 ATA with profiles varying from rapid to slow, with up to four decompression stops of up to 60 min each. Maximum likelihood analysis was used to estimate the relative decompression risk on a per unit pressure basis (termed “potency”) and the rate of gas uptake and elimination, both factors affecting the decompression sickness risk, from a specific dive profile. H2 potency for causing decompression sickness was found to be up to 35% greater than that for He. Uptake rates were unresolvable between the two gases with the time constant (TC) estimated at ∼2–3 min, leading to saturation in both cases in <15 min. Washout of both gases was significantly slower than uptake, with He washout (TC ∼1.5–3 h) substantially slower than H2 washout (TC ∼0.5 h). It is unknown whether the decompression advantage of the faster washout of H2 or the disadvantage of its increased potency, observed in the rat, would be important for human diving.