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What is Nitrogen Narcosis?

24 Feb 2018 ="post-tag" > Written by  ="post-tag" >
What is Nitrogen Narcosis?

Legendary French undersea explorer (and inventor of scuba-diving) Jacques Cousteau has a book named ‘The Silent World’, written in the late 1940's.  There is a chapter entitled ‘Rapture of the Deep’ which tells the story of Cousteau’s good friend Frederic ‘Didi’ Dumas, who was trying to deep dive in the Mediterranean Sea. They were in about 70 metres of water, and Didi was to descend on a line to the greatest depth he could reach and then release his weight belt and tie it on the line from the ship to the ocean floor. Didi describes the dive like so:

     "'The light does not change color as it usually does underneath a turbid surface. I cannot see clearly. Either the sun is going down quickly or my eyes are weak. I reached the hundred foot knot. My body doesn't feel weak by I keep panting. The damn rope doesn't hang straight. It slants off into yellow soup. It slants more and more. I'm anxious about that line, but I really feel wonderful. I have a queer feeling of the beatitude. I am drunk and carefree. My ears buzz and my mouth tastes bitter. The current staggers me as though I had too many drinks. "I forgotten Jacques and the people in the boats. My eyes are tired. I lower on down, trying to think about the bottom, but I can't. I'm going to sleep, but I can't fall asleep in such dizziness. There's a little light around me. I reach for the next knot and miss it. I reach again and tie my belt on it. Coming up is merry as a bubble. Liberated from weights I pull of the rope and bound. The drunken sensation vanishes. I'm sober and infuriated to have missed my goal. I pass Jacques and hurry on up. I am told I was down seven minutes.'

Didi's belt was tied 64 metres down. No independent diver had been deeper, yet Dumas' impression was that he had been slightly under 30 metres - insert your own Dumas/Dumb-ass joke here.

 This was the first widely read description of the affect nitrogen has under pressure. The wonderfully evocative name Cousteau gave it, ‘Rapture of the Deep’, is now more commonly known as ‘Nitrogen Narcosis’, or ‘Inert Gas Narcosis’ to diving nerds.

jacques cousteau 1426379c

So what is it?

Nitrogen Narcosis is a phenomenon linked to increased pressure. It is defined as "a reversible alteration of the state of consciousness of an individual in deep diving with compressed air". I’ve read this description 3 times now, and am still not quite sure what it’s going on about, so here we will try to look at it in terms a normal person will understand.

Simply, lots of gases are intoxicating when mixed with 21% oxygen – the amount we’re breathing right now (I hope). It depends on the pressure, and also how easily the gas dissolves in fat. Most of what we’re breathing is nitrogen, and the most accepted theory is that when we’re diving communication between the neurons in our brain, which is based on nitrogen bridges, is disturbed. As you know, while diving we accumulate nitrogen in our body, and one of the places where nitrogen tends to gather are these bridges, which increases the distance between the neurons. The longer the distance, the more time they need to communicate – leading to the feeling of being drunk and confused, kind of like a normal night at the Koh Tao Ladyboy Cabaret but with less stubble.

  If you dive deep you will get ‘narced’ because of this nitrogen narcosis. What happens to you depends on several factors, just like with alcohol – some people will feel it at relatively shallow depths, some can handle it much better. The reaction is said to be due to personality, body size, fat content, and mood - if you go looking to feel narcosis, then chances are you will!  It’s also very common with divers to feel the narcotic affect may be stronger from one day to the next keeping all the variables the same, which appears to suggest that the more a diver encounters nitrogen narcosis the better it is tolerated. 

So what does it feel like?

It’s bloody great! It all starts with a small tingling sensation in the stomach, which then begins to feel like a little euphoria. It’s almost unnoticeable at first, but slowly that euphoria moves from the stomach to the brain and then suddenly everything becomes amazing! The sandy bottom, the boring little brown fish you’ve never looked at before, the sun shining down from the surface…it's the best dive you've ever dived! There are many stories of divers removing their clothing to be more ‘free’, trying to get the fish to use their regulator to breathe from, refusing to acknowledge attempts to get them to shallow up, forgetting basic hand signals they’ve time and again in the past – personally on my deepest dive of around 50 metres I forgot how to work my dive computer, (which I’ve used on thousands of dives before) and spent what a good few minutes just staring at it, laughing at my stupidity whilst sitting down on the ocean floor, happy as a clam.


How should I deal with it?

Everyone gets ‘narced’. It’s a fact that if you dive deep, then your body will be affected by it, be it a small amount of reg-out-pants-down-craziness. Your only options is either to ascend to shallower waters to make it disappear, or you learn to deal with the narcosis. To become a better deep diver, consider the following:

-Get more experience: Experience works well as advice for everything related to scuba diving. Remember this: the more you dive, the better you will deal with any problem or other occurrence underwater, and as we just learnt the more deep dives you do (exposing you to the effects of the nitrogen narcosis) the more you’ll be able to handle it when it does inevitably kick in.

-Practice skills you may have forgotten: There are some very important skills (such as out of air scenarios) that you may have forgotten over time. Usually, the longer it was since you completed your Open Water certification, the less you’ll remember if the time ever comes when you need to use this. It’s a great idea to practice them in shallow water repeatedly until they become instinctive, so if there’s ever an emergency situation whilst at the same time being narced, you will be able to deal with it without thinking.

-Improve your buoyancy:  It is important that you are able to breathe and move slowly whilst diving. The key word here is be calm. If you are calm, everything will be less stressful and you will take better decisions when narced. You will never manage this if your buoyancy is poor, with lots of erratic movements. The SSI/PADI Perfect Buoyancy specialty will certainly help any diver who feels like they need to improve this aspect of their diving.

-Get further training: Take the PADI or SSI Advanced Course or the Deep Diver specialty, where you’ll be partnered with a professional who is used to dealing with nitrogen narcosis. Enjoy your narcosis and let your instructor keep an eye on you!


Lastly, no matter what your experience level is the trick is not to be afraid of narcosis, and try to embrace it as the fun that it is – you’ve probably noticed that experienced divers LOVE to go deep, so why not join the gang and give it a go yourself!

You can sign up for your PADI and SSI Advanced or Deep course in person or online, with courses starting every day here at Big Blue.

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