Below what temperature will a diver lose heat faster than it can be replaced without protection?

A diver loses heat to the surrounding water primarily through conduction, which occurs rapidly in colder environments. The temperature at which a diver begins to lose heat faster than it can be replenished typically aligns with body temperature regulation and factors influenced by the thermal properties of water.

Water is a much more effective conductor of heat than air; thus, even temperatures that might seem warm when compared to air can lead to heat loss in water. The body generally maintains a core temperature around 98.6°F (37°C), and as the water temperature drops, the rate of heat loss increases.

At 80°F, a diver is still within a range where they might not feel immediate effects, but the cumulative effect over time, especially with prolonged exposure, can lead to noticeable heat loss. Once you move below this threshold—specifically at around 75°F—many divers begin to experience the risk of hypothermia if they are not wearing insulating garments.

The choice of 80°F as the correct temperature highlights that below this point, the diver is more likely to lose heat faster than it can be replaced, particularly during extended immersion or when the diver is inactive. This concept underscores the importance of thermal protection in diving to maintain body heat in cooler water temperatures.