What does "surface interval" refer to in diving?

The term "surface interval" in diving specifically refers to the time spent at the surface after a dive and before the next dive. This period is crucial for allowing the body to off-gas excess nitrogen that has accumulated in the tissues and bloodstream during the dive. When divers descend underwater, they are exposed to increased pressure, which causes nitrogen from the breathing gas to dissolve into their bodies. As a diver ascends and returns to the surface, the pressure decreases, and this nitrogen must be released safely to prevent conditions like decompression sickness.

During the surface interval, divers can also monitor their health, hydrate, and prepare for any additional dives, always ensuring they follow appropriate safety protocols. The need for a sufficient surface interval is rooted in the physics of gas exchanges and is essential for ensuring safe diving practices.