Why is a surface interval important in diving?

A surface interval is crucial in diving primarily because it permits nitrogen to be eliminated from the body. When divers descend underwater, they experience increased pressure, which affects how gases dissolve in their body tissues. Nitrogen, being a key component of the air we breathe, can build up in the body during dives. If a diver ascends too quickly or undertakes multiple dives without adequate surface intervals, there is a risk of decompression sickness, commonly known as "the bends," due to the formation of nitrogen bubbles in the bloodstream.

During the surface interval, the body has the opportunity to off-gas nitrogen, reducing its concentration in the tissues and minimizing the risk of complications. This off-gassing is a natural process that occurs as the pressure normalizes back to atmospheric levels, allowing the body to safely release excess nitrogen before the next dive.

While relaxing, conducting equipment checks, and other reasons may be beneficial aspects of a surface interval, the paramount importance lies in allowing the body to rid itself of nitrogen, ensuring the diver's health and safety for subsequent dives.