Have you ever seen a herd of zebra or an Asian elephant running towards you underwater? Couple of mermaids swimming peacefully, chasing you to follow them?
Don’t worry, you didn’t go nuts. But this is also something out of favor.
Nitrogen narcosis is simply “being tipsy underwater.” But why and how this happens?
It is the pressure of only one gas in a gas mixture. Let’s take air as an example. Because the other gas is so few in the mixture, I only assume air is a mixture of oxygen and nitrogen.
Air = Oxygen + Nitrogen => Air consists of 20% oxygen and 80% nitrogen.
So, on the surface:
1 atm of Air = 0.2 atm of Oxygen + 0.8 atm of Nitrogen => In every 10 meters, pressure increases 1 atm
In 10 meters:
2 atm of Air = 0.4 atm of Oxygen + 1.6 atm of Nitrogen
In 20 meters:
3 atm of Air = 0.6 atm of Oxygen + 2.4 atm of Nitrogen and this goes on like this to other depths.
Dalton says that “total pressure of a gas mixture that is formed by non-reactive gases equals to the sum of partial pressures of each these single gases that form the mixture.”
What Is Nitrogen Narcosis?
When the partial pressure of nitrogen increases, it becomes anesthetic for us. The reason behind this is still unknown. For divers, this means that when we go deeper, nitrogen becomes more anesthetic for us.
Also known as Martini Law, states that “a diver is effected underwater as if he/she has drunk 1 shot of Martini in every 10 meters.”
This means that in 10 meters, you are effected like you have drunk 1 shot of Martini. In 40 meters, it is like a diver drank 4 shots of Martini.
Signs and Symptoms of Nitrogen Narcosis
These signs and symptoms are just like the ones with drunkenness.
- Excess self-confidence
- Difficulty in concentration
- Hallucinations (herd of zebra and mermaids in the open line)
- Recession in coordination
- Difficulty in communication
To be able to stay away from nitrogen narcosis, you should be diving no deeper than 30 meters. In almost every dive agency, 30 meters is the “suggested deepest point” in recreational dive.
Shallow dives (above 30 meters) is a precaution for nitrogen narcosis.
However, if you’d like to dive up to 40 meters (with proper deep dive training), your buddy should have already been in that depth before.
Don’t forget that the absolute maximum depth of recreational scuba diving is 40 meters.
Treatment of Nitrogen Narcosis
If you are experiencing any of the symptoms, you should ascend a little bit until the symptoms disappear. Because it is something related to the increased pressure, the aim is to decrease it. Divers can go on their dives after they feel okay, but should not descent to the point they have experienced the narcosis again.
If you see that you buddy seems to be out of his/her mind, having foolish movements (unless your buddy is always like this, lol) you should first ask your buddy to ascent a little bit. If he/she doesn’t respond, hold him/her from the BC or tank valve and help to ascent till the symptoms disappear.
A Real Life Scenario
In one of my dives that I am leading, we were in 35 meters with a couple of deep diving specialty students. The weather was very calm so we were using the anchor line as a reference to 40 meters. I have realized that one of the students has slowed down descending and left the anchor line.
I swam towards to him and asked him if he is okay. He was looking at me, but his response was very slow. I asked him to hold on to the anchor line. He tried to hold it but could only do it in his 3rd try.
I signed “up” to him and the whole group. He couldn’t realize that we started to ascent. Then I held his tank valve and carried him to 30 meters. He looked at me and signaled “okay.” Right after this, we went on our dive in 30 meters.
Nitrogen narcosis looks like an innocent diving disease. However, it can be fatal.
Diving without a dive buddy, not knowing about the nitrogen narcosis theory and/or diving deeper than the recreational dive limits can have really bad results including death.
If you are diving alone, untrained and don’t understand that you are experiencing nitrogen narcosis (totally ignorance), you would possibly go on descending. That’s because nitrogen narcosis increases your self-confidence.
People in narcosis usually tend to remove their mask and/or regulator.
I advise you to
- Dive shallower than 30 meters even though you have the proper deep diving training.
- If you like to dive up to 40 meters for a special purpose (a wreck in 38 meters, for example), always dive with a buddy who has already been in that depth without experiencing nitrogen narcosis.
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