SSI Open Water Diver Practice Exam Prep: Study Guide & Practice Test

Staying at designated stops during ascent is a critical safety practice to avoid decompression sickness, also known as 'the bends.' During a dive, divers absorb nitrogen from the air they breathe, which can dissolve in their bloodstream and tissues under pressure. As divers ascend, the pressure decreases, and nitrogen that has been absorbed starts to come out of solution. If a diver ascends too quickly, this nitrogen can form bubbles in the bloodstream, leading to serious health issues.

By incorporating safety stops, typically at depths of around 3 to 5 meters (10 to 15 feet), divers allow more time for the nitrogen to safely leave their system more gradually. These stops give the body a chance to off-gas the nitrogen more effectively, thus greatly reducing the risk of bubbles forming in the tissues or bloodstream. This practice enhances safety significantly, particularly on deeper or longer dives, where nitrogen absorption is more pronounced.