What can cause decompression sickness (DCS)?

Decompression sickness (DCS), commonly referred to as "the bends," primarily occurs when a diver ascends too quickly from depth. During a dive, divers breathe compressed air, which increases the amount of nitrogen dissolved in their body tissues and bloodstream. As a diver ascends, the pressure decreases, and nitrogen comes out of solution and forms bubbles if the ascent is too rapid. These bubbles can cause various symptoms, ranging from joint pain and dizziness to more severe neurological issues when they form in the bloodstream or tissues.

While overexertion during diving can contribute to fatigue or increase the body's nitrogen uptake, it is not a direct cause of DCS. Low oxygen levels can affect a diver's performance and safety but do not lead to decompression sickness. Similarly, high carbon dioxide levels can result from poor breathing practices and can cause other issues but do not directly cause DCS. Therefore, the rapid ascent from depth is the primary mechanism through which decompression sickness can develop, as it directly impacts the nitrogen levels in the body.