Hypothermia is a serious risk for scuba divers, even in places considered to be warm water diving. It occurs when the body loses heat, causing core temperature to drop below 95°F (35°C). Early signs include shivering, numbness, and clumsiness. As it progresses, symptoms can escalate to confusion, slurred speech, and loss of coordination. Treatment includes removing wet gear, providing warm, dry clothing, and applying external heat sources.

Severe hypothermia can lead to unconsciousness and even cardiac arrest. If a diver is showing signs of moderate to severe hypothermia—such as confusion, slowed breathing, or lack of shivering—they need immediate medical attention.

The other complication I mentioned earlier is the link between hypothermia, circulation, and decompression sickness. When a diver is cold, blood vessels constrict as the body prioritizes keeping vital organs warm. This reduced circulation to the extremities means less efficient nitrogen off-gassing, increasing the likelihood of nitrogen bubbles forming in the tissues upon ascent. Rapid rewarming after a dive can also trigger sudden circulation changes, potentially mobilizing nitrogen bubbles that had previously been safely stored in tissues. This is why it’s not a good idea to jump into a hot tub right after a dive.

To reduce risk, divers should stay warm before, during, and after dives, use adequate thermal protection, and monitor their body temperature to ensure safe circulation and off-gassing throughout the dive. If DCS symptoms occur, the diver needs emergency medical treatment, including oxygen administration and possible recompression therapy.

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