During your scuba diving training you will have come across the term, ‘Gas or Nitrogen Narcosis.’ You may have even heard of people getting ‘narced’ during a dive. But what does it actually mean and how does this affect our diving? In this article, we look at what is nitrogen narcosis, the physiology behind it, what the treatment is if we feel the effects of narcosis, and better yet, how to prevent nitrogen narcosis.
What is Nitrogen Narcosis?
Breathing nitrogen at higher pressures induces an altered state of consciousness, called nitrogen narcosis. It is similar to the effects of alcohol intoxication and increases in intensity at greater pressure, therefore the deeper you go.
Any gas used as a substitute for nitrogen in a breathing gas mixture has the potential to cause narcosis. Not just nitrogen. Nitrogen is simply what is commonly in our atmosphere already and most widely used as an inert breathing gas. This is why, however, we now more accurately refer to this phenomenon as ‘inert gas narcosis‘.
Some fear it, others seek it out. It is both innocent fun and has the potential to be deadly. Divers refer to it as ‘rapture of the deep‘ or the ‘Martini effect‘.
In 1953, Jacques-Yves Cousteau referred to his experiences under gas narcosis as ‘rapture of the deep’. He explained how it beckoned him to continue deeper. This is comparable to alcohol, where often people drink more than they should. This similarity is where the phrase ‘Martini effect’ or ‘Martini law’ came to fruition. It is said that diving deeper is like drinking one dry Martini on an empty stomach for every ten meters. Starting at 30 meters deep.
What Causes Nitrogen Narcosis?
Research into the field of nitrogen narcosis physiology is ongoing and difficult to conduct since the effects of inert gas narcosis are observed first and foremost by the victim. Recollection under extreme circumstances is not always clear. Similar to a blackout from intoxication.
What is known today is that its intensity depends on a gas’s lipid solubility. The higher lipid solubility, the greater the narcotic effect potential of that gas. What is lipid solubility? In layman’s terms, it is the ability of a gas to dissolve into fats, oils, and lipids. The more efficiently a gas dissolves into our body’s lipids, the greater the narcotic effect.
Not all gases have narcotic properties. Helium and neon, for example, do not cause any narcosis. Commercial and technical divers use helium for this very reason. Everyone is susceptible to nitrogen narcosis to varying degrees. While some divers learn to manage its effects it is not possible to develop a tolerance.
Nitrogen Narcosis Symptoms
The common symptoms of inert gas narcosis are:
- Perceptual narrowing
- Feeling lightheaded
- Trouble focusing on even simple tasks
- Slowed reaction time
Is getting ‘Narced’ Dangerous?
Nitrogen narcosis stories are fascinating. Some of the stories are funny, and some of them are dangerous, with fatal conseqeuences.
The funny narcosis stories are fairly harmless; maybe a diver could not stop giggling at a fish underwater. Or perhaps, they were distracted by a shiny shell. Either way, these fun narcosis stories are often under complete supervision by a dive buddy who is a professional and/or experienced scuba diver.
Read More: What Should Divers Do For Their Own Safety?
The dangerous narcosis stories are riskier scenarios and are more common at deeper depths. Divers forgetting to check their air gauge or no-decompression limits. Or going beyond their training limits and luring themselves to a deeper and more dangerous depth.
These dangerous situations are generally when divers become overly confident and dismiss the effects of nitrogen narcosis. We do not want to downplay the potential dangers of inert gas narcosis, however, let’s look at a few facts that can prevent dangerous situations:
- It is depth-related, 30m or deeper
- You can set your own limits
- The recommended recreational depth limit is 40m so divers should not be exceeding this
- If it occurs, there are no long-term negative effects
- It is easy to recover underwater by ascending slightly
So as a recreational diver as long as you stay within your limits, the potential of narcosis is more enjoyable than it is dangerous.
Nitrogen Narcosis Death
On the other hand, divers that push their training limits are more susceptible to very intense levels of narcosis. At greater depths, narcosis can become uncontrollable and very dangerous. Symptoms intensify at greater depths and cause confusion, impaired coordination, lack of concentration, hallucinations, and even unconsciousness. In James Clark’s study, he found that gas narcosis could be directly responsible for 6% of all diving fatalities.
With this in mind, always dive within your limits.
Nitrogen Narcosis Prevention
To ‘prevent’ inert gas narcosis we need to use a breathing gas mixture that does not consist of a gas with high lipid solubility. This is why deep divers prefer helium. Helium is relatively rare in our atmosphere, meaning it is a rather expensive choice.
Recreational divers limit their depths in order to manage narcosis. In adults it does not commonly occur at depths shallower than 30m. Most recreational training bodies limit certifications to 40m at which it is still a manageable amount of narcosis for most people.
Never dive alone, especially when you are diving deeper.
Nitrogen Narcosis Treatment
What do I during a dive where my narcosis feels very strong and makes me uncomfortable?
- Stay calm
- Restore proper deep breathing
- Try to signal your buddy
- Slowly ascend to a shallower depth
- Wait for symptoms to subside
There are no long-term negative effects and if you recover underwater there is no need to end the dive.
Not diving at all of course prevents it too.
Nitrogen Narcosis vs the Bends
Nitrogen causes both inert gas narcosis and decompression sickness. However, the two are not to be confused. Decompression sickness, or ‘the bends‘, is caused by the formation of nitrogen bubbles in your body tissues in the event of a rapid ascent or overexposure. On the contrary, the chief cause of nitrogen narcosis is nitrogen’s lipophilicity in combination with elevated pressure at its breathing depth.
So, there you have it. Next time someone asks you ‘what is nitrogen narcosis?’ you should have a good grasp on it and be able to explain it better.
Ever experienced narcosis yourself or witnessed it in your dive buddy? Please share your story in the comments below.