Why do scuba divers become dehydrated while diving?

Scuba divers become dehydrated while diving primarily due to the humidification of dry inhaled air. When divers breathe compressed air underwater, the air supplied to them is drier than the air at the surface. The lungs require moisture to maintain health, and the body works to humidify this dry air before it enters the lungs. This process consumes internal moisture, leading to dehydration, especially during longer dives.

As a result, even though divers are surrounded by water, they are still at risk of dehydration because the body is losing moisture in a way that can be counterproductive to hydration levels. This factor becomes particularly important for divers who are not adequately hydrating before and after their dives.

Maintaining proper hydration is crucial for divers, as dehydration can impact overall physiological function, circulation, and even bubble formation during ascent, making it an essential consideration in dive planning and management.