Dive Health & Safety
Nitrogen narcosis: what it feels like and what to do
Nitrogen narcosis is a well-known effect of breathing gas at depth: an intoxicated feeling, impaired judgement, difficulty concentrating and drowsiness. Divers Alert Network notes that fatigue, depth, cold water, alcohol before diving and personal susceptibility make it more likely. It typically clears on its own when you ascend above the depth where it started — so if you feel it, go shallower.
By 71 Guardians · Published 18 Oct 2026
What does nitrogen narcosis feel like?
DAN describes an intoxicated feeling, impaired judgement, difficulty concentrating and drowsiness. Mood can swing from overconfidence or elation to anxiety. In one case DAN reports, a diver noticed narrowing vision, slowed thinking and a loud pounding in his ears, which faded after he ascended. Everyone is affected differently, and the effects can vary from dive to dive.
At what depth does narcosis start?
DAN's guidance is that on air or nitrox the onset is generally felt at around 80–100 feet (about 24–30 metres), and the effects grow more marked the deeper you go — but every individual is affected differently, and it can vary from dive to dive. At extreme depths of more than 122 metres, DAN notes divers can lose consciousness.
What makes narcosis worse?
- greater depth
- fatigue
- cold water
- alcohol before the dive
- personal susceptibility
What should I do if I feel narked?
Signal your buddy and ascend a few metres. Narcosis typically resolves when you come up above the depth where the symptoms began. DAN's case review is clear that the safest response is to end the dive rather than press on, and to talk about the risk with your buddies beforehand.
Frequently asked questions
Does nitrox prevent narcosis?
Don't count on it. DAN groups air and nitrox together when describing narcosis depths; nitrox is used mainly to reduce decompression stress.
Is narcosis dangerous?
The narcosis itself fades on ascent, but the poor judgement it causes underwater can lead to accidents — which is why you should ascend when you notice it.
Questions before you dive with us?
Message our team on WhatsApp — we're divers in Hurghada and happy to help.
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- Know the Risks — Alert Diver — Divers Alert Network (DAN)
- Breathing Gases — Alert Diver — Divers Alert Network (DAN)