Jacques Cousteau’s 1953 book, The Silent World, contains the first ever account of dive induced nitrogen narcosis, or raptures of the deep. In his story about descending to a depth of 210 feet, the deepest a diver had ever been at that time, Frederic Dumas described a feeling of anxiety blended with pleasure, sleepiness, and dizziness all at once. As he ascended from the dive and the rope he was following regained its shape, he came back to his senses, but did not realize that he had broken a record until others showed him proof. While getting narced at depths around 100 feet is sometimes described as a pleasurable experience, it can also lead to risk taking behavior and poor decision making. Let’s take a closer look at nitrogen narcosis.
The Physiology of Narcosis
While nitrogen narcosis, which is sometimes simply referred to as inert gas narcosis, usually happens at depths beyond 100 feet (30 meters), it can and does happen in shallower water at times, particularly if you are diving on simple compressed air – the same air we breathe on land. Nitrogen, which comprises about 79% of our usual air intake, is an inert gas that normally causes no problems. This changes when pressure is added while diving, as the gas’s lipid solubility increases. Eventually, your body overdoses on Nitrogen, causing difficulty with perception, comprehension, and more.
Warning Signs You’re Getting Narced
The symptoms of nitrogen narcosis vary from one person to the next, just as the intoxicating effects of alcohol can vary from person to person. Some divers feel giddy, others become anxious, and some can even become belligerent. The deeper you go, the more pronounced and varied your symptoms become. The best way to recognize your own warning signs before tunnel vision, hallucinations, and other symptoms set in, is to pay close attention to the way that you are feeling as you descend, and provide yourself with frequent reality checks.
Sudden lightheadedness or a feeling of confusion can be one of the initial signs of narcosis. Mild euphoria or a feeling of sudden intoxication is another. The more often you dive, the more easily you will recognize the feelings that signal the onset of narcosis; but keep in mind, the symptoms can vary from day to day and will sometimes arrive at different depths.
Decrease Your Accident Risk
Diver deaths attributed to nitrogen narcosis normally happen when recreational limits have been exceeded. At greater depths, the narcotic potency of nitrogen increases dramatically, causing a numbing effect and slowing normal response. For example, a photographer on the Andrea Doria was at 216 feet and it took an entire minute for that diver to put a flashbulb on a camera. One story tells of a diver attempting to break a depth record who died due to narcosis; his safety diver was observing him from a depth of 200 feet, and when he passed 350 feet, he removed his mouthpiece, tried to hand it to a passing fish, and then sank into the abyss some 3,000 feet below.
If you are planning to dive deep, then using Trimix or other technical gas blends like Heliox can prevent accidents from happening; and if you’re on Nitrox or Air in shallower depths, and you feel narcosis setting in, all you need to do is slowly ascend until the symptoms fade. Using a good dive computer and paying attention to alarms is another way to keep yourself safe.
Divers often learn to manage narcosis, but a tolerance for nitrogen overload can never be developed. Learn more and dive deeper by taking technical dive courses. You’ll be able to enjoy a completely lucid experience while remaining safe in the silent world.