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Drowning Danger: Experts Warn of Silent Water Blackout
18 Dec, 2025
Summary
- Shallow water blackout can affect anyone, even fit individuals.
- Hyperventilating before breath-holding drastically increases risk.
- Report co-authors share personal tragedies to raise awareness.
A new report, 'The Physiology Of Survival: Breath Hold Shallow Water Diving,' is being released to highlight the risks of shallow water blackout (SWB) and hypoxic blackout (HB). Co-authored by scientists who have experienced the tragedy of near-fatal incidents, the report aims to educate the public about how anyone, regardless of fitness, can lose consciousness underwater.
Professor Andrew Baker and Professor Hugh Montgomery initiated the report after personal tragedies. Baker's son George survived a hypoxic blackout in July 2022, while Montgomery's son Oscar tragically died snorkeling in 2020. Their shared experiences underscore the critical need for greater awareness regarding these often-misunderstood dangers.
The report explains that HB occurs during breath-hold swimming when rapid oxygen depletion leads to unconsciousness, and SWB happens during breath-hold diving as pressure changes near the surface cause oxygen levels to drop. Hyperventilating is identified as a significant risk factor, delaying the urge to breathe and increasing the likelihood of drowning.
