Nitrogen narcosis is a reversible alteration in consciousness that occurs when a diver breathes compressed air at depths greater than about 100 feet (30 meters). The effects of nitrogen narcosis are similar to those of alcohol intoxication, and can include euphoria, disorientation, impaired judgment, and loss of coordination.
Nitrogen narcosis is caused by the increased partial pressure of nitrogen in the diver’s body at depth. Nitrogen is a relatively inert gas, but at high partial pressures it can dissolve into the diver’s tissues and affect the functioning of the central nervous system. The effects of nitrogen narcosis can be exacerbated by cold water temperatures, fatigue, and stress.