Decompression (diving)

Decompression in diving refers to the controlled process of gradually reducing the pressure on a diver after they have been exposed to increased pressure at depth. This is crucial because dissolved inert gases (primarily nitrogen, but also helium and oxygen in some cases), absorb into the diver's body tissues at increased pressure. If the diver ascends too quickly, these gases can form bubbles in the bloodstream and tissues, causing a condition known as decompression sickness (DCS), also called "the bends" or "caisson disease".

The rate at which a diver decompresses is dependent on several factors, including:

• Depth: The deeper the dive, the greater the pressure and the longer the decompression stop(s) are required.
• Duration: The longer the time spent at depth, the more gas is absorbed, requiring a longer decompression.
• Diving gas composition: The type of breathing gas used (e.g., air, nitrox, trimix) affects the rate of gas absorption and the need for decompression. Helium, for instance, is less likely to cause DCS than nitrogen.
• Individual factors: Factors such as age, health, fitness, and level of hydration can influence the individual's susceptibility to DCS and therefore the required decompression profile.

Decompression procedures are typically planned using dive computers or decompression tables, which calculate the necessary ascent rates and decompression stops based on these factors. These stops allow the dissolved gases to be gradually released from the body tissues via the lungs, minimizing the risk of bubble formation.

Various decompression models and algorithms exist, each with its own set of assumptions and predictions regarding gas uptake and elimination. These models are constantly being refined as research into decompression sickness advances.

Failure to adhere to recommended decompression procedures can result in decompression sickness, a condition with a range of symptoms, from mild joint pain to severe neurological problems and even death. Treatment for DCS typically involves recompression in a hyperbaric chamber. Prevention through careful planning and adherence to decompression protocols is always the best approach.