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Updated: Jun 23, 2026
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A Model to Simulate Clinically Relevant Hypoxia in Humans
Published on: December 22, 2016
Risk of decompression sickness in extreme human breath-hold diving
1Department of Physiology and Biophysics, Dalhousie University, Halifax, NS, Canada.
Summary
Diving deeper increases decompression sickness (DCS) risk in breath-hold diving. Risk is negligible to 100m, then rises non-linearly, plateauing around 5-7% with lung collapse beyond 230m.
Area of Science:
- Physiology
- Diving Medicine
- Risk Assessment
Background:
- Decompression sickness (DCS) risk in breath-hold diving increases with depth.
- Total lung collapse may limit nitrogen uptake at extreme depths.
Purpose of the Study:
- To estimate DCS risk in deep human breath-hold diving.
- To model the relationship between dive depth and DCS probability.
Main Methods:
- Compiled database of breath-hold dives >= 100m (1976-2006).
- Modified probabilistic decompression models using maximum-likelihood estimation.
- Adjusted arterial nitrogen for lung compression and reduced cardiac output during apnea.
Main Results:
- Analyzed 192 dives by 24 divers; deepest was 209m.
- Two drowning fatalities and two DCS cases documented.
- Predicted DCS risk negligible to 100m, increasing non-linearly to a 5-7% plateau beyond 230m.
Conclusions:
- DCS risk in breath-hold diving is depth-dependent.
- Models predict a plateau in risk due to lung collapse at extreme depths.
- Findings align with existing data on deep breath-hold diving incidents.
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