What is Nitrogen Narcosis: Like Diving With Martinis

What is Nitrogen Narcosis: Like Diving With Martinis

How to avoid Nitrogen Narcosis

Keep this level - Credit: Konstantin Karchevskiy

Most divers have heard of nitrogen narcosis - but what is it, how does it work, and what do you do about it?

Nitrogen Narcosis Definition

Nitrogen narcosis, or more accurately inert gas narcosis, is a condition that hits many divers when performing deeper dives. Typically it will start at around 30 meters(100 feet) of water.

What is nitrogen narcosis?

Commonly referred to as nitrogen narcosis, it is now often referred to by the more accurate name of inert gas narcosis. It has been found that other gasses than nitrogen can cause the narcosis effect.

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Some even argue that any gas that can be breathed, save for a few such as helium, and cause this effect.

Divers, in particular in the US, often refer to inert gas narcosis as “the martini effect” or “Martini’s Law” as the effect is supposedly comparable to drinking one dry martini on an empty stomach for every 10 meters/33 feet descended beyond the first 20 meters/66 feet.

Symptoms of nitrogen narcosis

Click the image to read about the Deepest dive ever made - Credit: Littlesam

Nitrogen Narcosis Symptoms

Symptoms of Nitrogen Narcosis include

  • Dizziness
  • Emotional reactions such lightheadedness
  • Elation
  • Euphoria
  • Anxiety

Severe cases may also cause debilitating inertia, blindness, unconsciousness, and maybe even death.

Who gets Nitrogen Narcosis?

Inert gas narcosis theoretically affects all divers descending below 20 meters/66 feet, though the severity of the narcosis varies greatly from diver to diver. And even from dive to dive. For reasons not entirely understood.

How to be a Safer Diver: Emergency Planning for Diving

With experience, divers can learn to manage and cope with the effects of inert gas narcosis, but it is not possible, as far as we know now, to develop an actual tolerance.

deep diving with nitrogen narcosis

Diver going deep - Credit: Jon Milnes

What causes Nitrogen Narcosis?

The full cause of inert gas narcosis isn’t fully understood, but it is believed that a number of breathable gases react with the body’s tissues, in particular with the lipid, or fat, tissues.

As our brains consist predominantly of lipid tissues, the effect is mostly felt here.

The effects increase in severity as depth is increased, with most divers beginning to feel some effect at around 30 meters/100 feet, and these symptoms becoming severe at around 40 meters/140 feet.

This is one of the reasons, along with decompression illness and the risk of oxygen toxicity, for most organizations setting the recreational diving limit at 40 meters/140 feet.

Nitrogen narcosis treatment?

The remedy is as simple as descending to a shallower depth, after which the symptoms will subside with no known long-term effects.

In most cases, the dive can be continued at the new, shallower depth.

However, due to the feeling of euphoria and elation often caused by the narcosis, the affected diver may not be able to make the assessment that they are affected. Therefore they will not themselves make the decision to decrease their depth.

Because of this, it is important that buddies look out for each other on deep dives, and watch for any erratic or uncommon behavior that may be a sign of inert gas narcosis.

If these are spotted, your dive buddy should urge the diver to decrease their depth, or guide him or her up to shallower waters.

Don’t go Deep Diving alone

Nitrogen narcosis is a potentially severe condition, but luckily easy to manage.

Read Deep Diving: Rules, Recommendations And Fun Facts

Divers who are new to deep diving should always do their first ventures into the deep with experienced buddies or dive instructor. Make sure someone can assist you in case of “Martini’s Law”, until you’ve develop your own coping mechanisms for it.

And of course, maximum recreational dive depths should always be observed.

Have you ever been affected by Nitrogen Narcosis? Tell us about your experience in the comments below.

About The Author

Thomas Grønfeldt Senger

Thomas is a Naui Instructor and has been diving in Australia, France, Egypt, Sweden, Indonesia, Iceland, and numerous other locations around the world.


  1. Bruce Campbell

    Good points. Fortunately the effects can be overcome by going shallower. Another good reason to have a good buddy.

    • Torben Lonne

      Hi Bruce,

      Yes in this case a buddy is a good “investment” – and also why solo dives should be done shallow and within your personal limits.

  2. SKuba Steve

    Good information about inert gas vs. N2. The rule of thumb I use is that if you are below 66 ft you just have to assume that your going to be narced to some degree. I had an experience with a buddy where I thought he was completely narced and didn’t see a huge jelly ahead and above us… only to find that there was no jelly and I was the one that was narced lol!
    Skuba Steve
    The surface interval’s over… get out there and dive!

    • Aiman

      I like scuba steve

  3. richard p smith

    The effects on divers usually come under a group called the bends and the variation in behaviour has baffled researchers over the years when age/ sex/ experience/ years diving/training has all been cosidered. The x factor or factors need more research….. keep diving keep training and keep checking your buddy and hope he is checking you … safe diving.

  4. Dan Marston

    fortunately I’ve never experienced nitrogen narcosis I’ve only read about it and know what it is I’ve also heard it the rapture chances are I may never even make it to diving under the water I’ll be lucky to make it to the pool classes if and when I take scuba hopefully 2 or 3 years I also never would drink if I ever could and was gonna dive I really don’t know if my comments will matter to you I did find the article interesting reading when I did get to try scuba at the expos over 6 years ago I was in a small divepool I didn’t and never experienced anything like that can or could you in a divepool just asking and wondering for when I take scuba in the next years

  5. sandeep

    Good information useful for those going for Advance scuba diving course

  6. Alan

    Haven’t dove in years, but did so often a long time ago…at a time when tanks were only filled to 2250 psi, the ORCA EDGE was first available, and there was not the recreational dive limit of 130 ft. In 1973, we dove the Palancar in Cozumel every day for a week, 3 dives a day. The first dive was the “bounce dive” where we typically went down to 150 – 200 ft, frustratingly looking for black coral. Nitrogen narcosis first came on at ~110 ft, unless you drank a lot the night before, in which case it occurred at ~90 ft. It felt euphoric with the beautifully clear waters around the Palancar. What I noticed was how fast the effect increased, where by 180 ft, it felt like 4 – 5 beers. On one dive down the wall, I couldn’t clear my ears and stopped at 180 ft. A German women had gone down to ~200 ft and start dancing on a coral outcropping on the wall. Suddenly, the outcropping broke off and started rolling down into the depths. Too the surprise I think of everyone watching, she started rapidly swimming after it…straight down. Fortunately, Pedro, the safety diver who was at ~160 ft immediately dove down and retrieved her. On the dive boat, she remembered the incident, but thought the wall was a “flat bottom” and the rolling outcropping was just like “tumbleweed” rolling across the bottom.

    If you ever dive to depths where you think nitrogen narcosis is affecting you, a simple test would be to see how easily you can add single digit numbers in your head. You would be surprised even at relatively moderate depths.


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