Theory 03/Diving & Hyperbaric Physiology
Bubbles Are a Rate Ratio
Decompression sickness risk is set by the ratio of bubble nucleation rate to gas elimination rate rather than by peak supersaturation, so a slower ascent can be riskier than a faster one with better elimination.
01The mechanism
Bubbles form at nucleation sites when dissolved gas exceeds local pressure, and grow or shrink depending on the gradient. Elimination competes with nucleation for the same dissolved gas.
The ratio determines how much gas becomes bubbles rather than being exhaled, which is why profiles with identical supersaturation differ in risk.
02What this is not
Those use peak supersaturation. This uses the competition between nucleation and elimination, which explains profile-dependent risk.
03Predictions
- P1Risk should track the ratio across profiles.
- P2Improving elimination should reduce risk at equal supersaturation.
04Refutation
Risk tracking peak supersaturation would remove the competition.