When does decompression sickness typically occur?

Decompression sickness, often referred to as "the bends," typically occurs during the ascent phase of a dive. As a diver ascends from deeper depths, the pressure around them decreases. If a diver ascends too quickly, the nitrogen that has been absorbed into the body tissues under higher pressure can come out of solution and form bubbles in the bloodstream and tissues. This process is linked to the decrease in pressure as the diver rises, which can lead to various symptoms and, in severe cases, can become life-threatening.

Understanding this principle is crucial for safe diving practices, as it emphasizes the importance of controlled ascents and following safety stops to allow the body to off-gas nitrogen gradually. The other options, while they may relate to factors involved in diving or pressure changes, do not specifically address the physiological processes that lead to decompression sickness during ascent, which is the key to this topic.