When does long-term immersion hypothermia set in during cold water immersion?

Long-term immersion hypothermia is a serious physical condition that occurs when a person is exposed to cold water for an extended period. Immersion in cold water significantly affects the body's ability to maintain its core temperature. The onset of hypothermia can vary based on several factors, including water temperature, the individual's clothing, body fat, age, and overall health.

In cold water immersion, body heat is lost much more rapidly than in air, and it is generally accepted that the risk of hypothermia increases significantly after 30 minutes of immersion. After this duration, a person's ability to generate body heat diminishes, leading to a drop in core temperature and the possibility of developing long-term immersion hypothermia.

Responding to other timeframes, options suggesting earlier onset—like within 3-10 or 10-20 minutes—may reflect initial stages of hypothermia, but long-term consequences become critical largely after 30 minutes. Immersion hypothermia doesn't necessarily lead to severe symptoms right away but can escalate quickly after this threshold, warranting a thorough understanding of the environment and conditions that contribute to this serious condition.