Can nitrogen narcosis affect you at any depth?
You may be wondering at what depth does nitrogen narcosis occur? When are the symptoms of nitrogen narcosis (the narks) noticeable underwater?
Scuba divers breath nitrogen under pressure. This produces an intoxicating effect which is known as nitrogen narcosis. If you're wondering at what depth does nitrogen narcosis occur; the simple answer is that mild symptoms can occur at most depths and would start at around 10 metres (33 feet). However, nitrogen narcosis really only becomes noticeable on scuba dives at around 30 metres (98 feet) and deeper.
Nitrogen narcosis or the narks can occur during both shallow and deep dives. The narks or 'Raptures of the Deep', can start at around 10 metres (33 feet). But it's not usually noticed until you exceed the depth of around 30 metres (98 feet) of depth on a dive.
However, having said that each individual diver has their own threshold of susceptibility to the narks. Whereas a some divers may experience narcosis at 15 metres (49 feet), others can dive to 50 metres (164 feet) without any apparent side effects.
But also, as experienced by myself, some days you can be affected by nitrogen narcosis and others not. This will be down to a number of other factors. This can include the water temperature, how much sleep you've had the night before and your state of mind beforehand.
Nitrogen narcosis is brought about due to the over saturation of nitrogen in the body. But particularly to the brain.
Nitrogen forms 79% of the air that divers breath, assuming they're diving on atmospheric air. As a diver descends, the pressure of water increases. This results in the absorption of more nitrogen, which is due to the pressure increase. The deeper the dive, the greater the nitrogen absorption.
Example of 30 metre dive and pressure of nitrogen
For example, a diver at a depth of 30 metres (98 feet) underwater is breathing air that is four times more dense than at sea level. This is because the pressure in BAR at 30 metres is 4 Bar vs at sea level, which is a one Bar. Therefore, the air that this diver is breathing at 30 metres is at 4-times the pressure than it was before he entered the water. Therefore the quantity or pressure of nitrogen would also be four times greater.
It is usually once you dive below the depth of 30 metres you may find that some of the symptoms like euphoria or anxiety may kick in. Prior to this depth, you may have mild symptoms of nitrogen narcosis, but be unaware of the affects.
If any of the symptoms of nitrogen narcosis occur, the best way to alleviate the feelings or symptoms is to ascend a few metres or feet until the feeling(s) subsides.
Once the feeling or symptom has gone away, you can then continue your descent once more. Usually on the second attempt at diving deeper than 30 metres (98 feet), the feelings of nitrogen narcosis don't become apparent.
However, if the feelings or symptoms reoccur when you descend again, or if the feelings are severe, you are best advised to abort the dive.
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