Scuba divers who dive deeper than 30 meters are dangerously and severely affected by Nitrogen. The exact mechanisms behind nitrogen narcosis are still to be explored, but it has to do with nitrogen gas affecting the nerve transmissions in the body during high pressure. Nitrogen is not the only gas capable of affecting the nerve transmissions when the body experience high pressure; the same state of intoxication can for instance be caused by hydrogen and argon. Since the air inhaled by scuba divers contains a large amount of nitrogen (just like the air that we breathe above the surface every day), nitrogen narcosis was the first type of gas narcosis experienced by scuba divers, hence the name. Today, the condition is also referred to as Inert Gas Narcosis.
The effects of nitrogen narcosis are similar to the effects of anesthetic gas or alcohol. The well known diver Jacques Cousteau expressed it as the “rapture of the deep”. Since a diver needs to be focused and act responsible – and even more so at great depths – nitrogen narcosis can have disastrous effect. A diver can for instance forget to check how much air he or she has left, stay down to long or forget to do safety stops when ascending to the surface. Some divers have even begun to take off their equipment or tried to share their mouth piece with a fish. Nitrogen narcosis can also be lethal due to nitrogen poisoning.
It can be hard for the effected diver to realize that he or she is developing nitrogen narcosis, since the level of intoxication will increase gradually. It is therefore always important to keep an eye on your partner during the dive and try to detect illogical behaviors. Many divers regularly check the mental state of their buddy by showing the buddy a number of fingers. Before the dive, the divers have agreed that when 3 fingers are displayed, the buddy must respond by showing 2 fingers, when 8 fingers are displayed the buddy should hold up 7 fingers and so on. A diver suffering from nitrogen narcosis might calculate the wrong number, or display a number of fingers that is not coherent with the number that he or she calculated. The diver can also loose interest in carrying out these safety checks and ignore the buddy.
If you suspect that you or your buddy is suffering from nitrogen narcosis, you should immediately begin your ascent to shallower depts. Never panic and head for the surface as quickly as possible, safety stops are imperative. The effects of nitrogen narcosis will usually wear of as soon as you reach shallower depths, even if they are far from the surface. Sometimes an affect buddy can be very reluctant to ascend, since he or she is not aware of the problem. Before embarking on a deep dive, it can be a good idea to agree on a sign that means “Nitrogen narcosis, we must ascend”.
Never dive below 20 meters unless you have completed your deep-dive training. During the training, you will learn more about how to avoid nitrogen narcosis. A rapid descent should be avoided since it will make the pressure increase very quickly and nitrogen gas dissolves more slowly in the blood than many other gases. Nitrogen narcosis seems to be more common during dives where the diver has made a rapid descent, but it can occur even after a very slow descent. Many experienced divers recommend a descent at a very steady pace when deep-diving, since this will prevent any sudden changes and unbalanced solution of gas in the blood. This method has however not been scientifically proven.
Never use sedating drugs, including alcohol and marijuana, before you go scuba diving. Any sedating drugs will increase the risk of nitrogen narcosis. Keep in mind that THC is stored in your body for long periods of time. Even though these kind of sedative medications are prescribed by a physician it should be avoided before dives.