Nitrogen narcosis, also known as "rapture of the deep," is a narcotic sensation that divers usually experience at depths beginning at 100 feet. This is caused by the increased pressure of the nitrogen in the body, and its effects intensify as you dive deeper.
The symptoms of nitrogen narcosis are often compared to alcohol intoxication. It impairs judgment and motor skills, so divers experiencing serious narcosis pose a danger to themselves as well as those they dive with.
Individuals vary in their tolerance to nitrogen. Some divers are seriously affected at depths approaching 100 feet, while others show little to no impairment. A diver's tolerance can also vary from one dive to another, so never assume that you know your personal tolerance to nitrogen narcosis.
Responding To Nitrogen Narcosis
The symptoms of nitrogen narcosis reverse immediately as you ascend, so make your way to shallower water as soon as you feel affected. You can continue the dive once symptoms have disappeared, and your body will suffer no side effects.
When diving at depths where narcosis is a risk, observe the actions of your buddy for signs of impairment. Often divers exhibit signs of impairment without realizing that they are experiencing nitrogen narcosis. If your buddy appears to have difficulty with simple tasks, acts carelessly, or displays signs of panic, you should immediately assist your buddy to shallower water.
Preventing Nitrogen Narcosis
The best prevention against nitrogen narcosis is avoiding unnecessary depths. This is one reason why the maximum depth for recreational scuba diving is 130 feet.
Other factors that increase the effects of nitrogen narcosis include alcohol, fatigue, illness, medications, and anxiety. These factors do not cause narcosis by themselves, but when combined with pressurized nitrogen, can intensify the symptoms.