What does decompression sickness result from?

Decompression sickness, often referred to as "the bends," occurs primarily due to ascending too quickly after diving. During a dive, divers experience increased pressure, which allows more nitrogen to dissolve in their bodily tissues. If a diver ascends too quickly, the decrease in pressure happens too rapidly, causing the nitrogen that has been absorbed in the tissues to come out of solution too quickly, forming bubbles. These bubbles can cause a variety of symptoms depending on where they form in the body, which can include joint pain, dizziness, difficulty breathing, or in severe cases, paralysis or death.

The other choices pertain to different physiological issues or general diving safety concerns but do not directly relate to the root cause of decompression sickness. Inhaling excess oxygen can lead to oxygen toxicity but does not cause decompression sickness. Inadequate conditioning might affect a diver's overall performance, but it is not a direct cause of decompression sickness. Excessive time spent underwater could lead to increased nitrogen absorption, but without a rapid ascent, it does not automatically lead to decompression sickness. Therefore, the correct understanding focuses on the relationship between ascent rate and nitrogen release.