What is Nitrogen Narcosis: Like Diving With Martinis

What is Nitrogen Narcosis: Like Diving With Martinis
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.

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

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 as 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  66 feet (20 meters), 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.

Diver going deep
Diver going deep
Photo by: 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 increases, 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 the case of “Martini’s Law” until you’ve developed 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.


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I have learned my signs of Nitrogen Narcosis way back when I was young and eager to go really deep. Luckily I’ve had three good friends along (all photographers), and we used to take care for each other; diving in pairs, one would only take photos, while the other would carry a double set of instruments (analog decompression meters, depth meters and a watch) defining the diving profile for the both. The next day the roles were swapped, etc.
My personal signs were, first the strong metallic taste of the air, with its usual syruppy density (of volume at depth) and its common Enzis compressor oil component. That made me become alert, and several minutes later I would experience the visual curiosity – as if the last image I’d see was reluctant to leave me when I was already looking at something else! It’s like turning your eyes away from something, and feeling the image dwell there for a while before the new scene registered.
This was always enough to quit that depth and go up five or so meters. Interestingly, it never happened down to 40 meters, more like about 60 or so, and my tolerance to these effects became better with time if I was diving every day throughout of my holidays. I guess it has something to do with physical condition too.
In those times it was believed that the person under Nitrogen Narcosis will behave exactly as they behave under the influence of alcohol, and the instructors took care to combine the diving buddies from two different types: a choleric with the phlegmatic, etc.
Whichever type you and your buddy are… NEVER stop observing each other, and always sign to each other how you feel! Let the more sensitive diver dictate the dive profile – the other one has to comply! Dive Safe – and enjoy! 🙂


I am a recreational diver so 130’ is my limit. In 3 years I have 250 dives and Master Diver cert which included the Deep Diving cert. My instructor for this had a very memorable mantra,”It is not how deep you dive but how you dive deep.” For me this translates into many does and don’ts.
Do get a good night sleep and don’t drink for a few days before diving. On some dive trips I dive 25 times in a week and my dive computer shows 30 hours of no fly time. I enjoy the feeling of nitrogen tissue saturation but I realize that the dangers this presents when diving and on deck. I wait until my last dive sometimes 5 or 6 days before having that first beer and starting to pack my gear and count down the “no fly time”. Do get a good dive computer so that you can plan your dive profiles for each and every dive. Do respect no fly time. Don’t get lazy on 3rd and 4th dives of the day especially in a warm water familiar location. Double check your equipment analyze your tank check pressure, etc. Plan your dive and check bottom time especially if you are going below 60’. For me Scuba diving is super fun and relaxing. I am looking forward to getting another 250-300 in the future.


Just experienced the adverse effects of narcosis today. I thought it was supposed to be a pleasant feeling but for me it wasn’t. Mine came on at 120feet. It started with severe dizziness and then my heart just began racing and I was shaking uncontrollably. I knew what it was and signalled my buddy who helped me ascend a little, once I had gone up probably 10feet I felt a lot better but the experience scared me so I decided to end my dive early and make my way onto the boat. During my safety stop I began shaking and just wanted to be back on the boat. Every part of me wanted to go straight to the surface but I had to just restrain myself. I’m only sharing my experience so that other people know how it effected me and that it’s ok to freak out.


I like scuba steve


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.


Good information useful for those going for Advance scuba diving course

Dan Marston
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

richard p smith
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.

SKuba Steve
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!

Torben Lonne
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.

Bruce Campbell
Bruce Campbell

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

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