What is the purpose of a decompression stop?

The purpose of a decompression stop is to allow excess nitrogen to escape safely from the body during ascent. When divers go underwater, they breathe air that contains nitrogen, which dissolves in the body's tissues under pressure. As divers ascend, the pressure decreases, and nitrogen comes out of solution. If a diver ascends too quickly, this nitrogen can form bubbles, leading to decompression sickness, commonly known as "the bends."

Decompression stops provide a controlled way for divers to pause at specified depths during their ascent. This allows time for the nitrogen to be safely off-gassed from the tissues into the bloodstream and ultimately to be exhaled. The stops are typically plotted on dive tables or dive computers based on the dive profile and the time spent at depth. This process is critical in ensuring diver safety and preventing potential injuries related to decompression sickness.