What is nitrogen narcosis?

Nitrogen narcosis is a temporary effect that happens when breathing gas under pressure at depth makes you feel lightheaded or mentally foggy. It’s often compared to feeling mildly drunk or euphoric. The deeper you go, the stronger the effect becomes, and your ability to think clearly or make good decisions can fade without you realizing it. It usually begins to appear around 80 to 100 feet (24 to 30 meters) on air.

Every diver is different. Some feel the effects strongly, while others notice nothing at all, even on the same dive. I’ve been to 100 feet on air and felt completely normal, but that doesn’t mean I’m immune or that you will have the same experience. The difference is individual tolerance, not skill. Narcosis is always present to some degree, even if you don’t feel it, and the only reliable way to make it fade is to ascend to a shallower depth.

Divers can also reduce the effects by changing the gas they breathe. Recreational divers sometimes use enriched air nitrox, which contains more oxygen and less nitrogen, slightly reducing narcosis at moderate depths. Technical divers go further by using gases like helium or hydrogen, which replace some of the nitrogen and allow safer operation at greater depths.

Risk vs Hazard

Not all hazards are dangerous. Hazards are things that can hurt you and risk is the chance they actually will. Inspired by The Human Diver's approach to safety.

Is Scuba Diving Dangerous?

Scuba diving looks risky, but how dangerous is it really? Learn the facts, common risks, safety stats, and how divers stay safe underwater.

Understanding Nitrogen Narcosis

Learn what it is, how it affects divers at depth, and how to manage its risks. Includes symptoms, mitigation strategies, and why it’s a concern.