What is nitrogen narcosis?

Nitrogen narcosis is a condition that affects deep-sea divers. It goes by many other names, including:

  • narks
  • rapture of the deep
  • the martini effect
  • inert gas narcosis

Deep-sea divers use oxygen tanks to help them breath underwater. These tanks usually contain a mix of oxygen, nitrogen, and other gasses. Once divers swim deeper than about 100 feet, the increased pressure can alter these gasses. When inhaled, the altered gasses can produce unusual symptoms that often make a person appear to be drunk.

While nitrogen narcosis is a temporary condition, it can have serious health consequences. Read on to learn more about the symptoms of nitrogen narcosis and what to do if you or someone else experiences them.

Most divers describe nitrogen narcosis as feeling like they’re uncomfortably drunk or dazed. People with nitrogen narcosis often appear that way to others too.

Common symptoms of nitrogen narcosis include:

More severe cases can also cause someone to go into a coma or even die.

Nitrogen narcosis symptoms tend to start once a diver reaches a depth of about 100 feet. They don’t get worse unless that diver swims deeper. Symptoms start to become more serious at a depth of about 300 feet.

Once a diver returns to the water’s surface, the symptoms usually go away within a few minutes. However, some of the symptoms, like disorientation and poor judgment, cause divers to swim deeper. This can lead to more serious symptoms.

Experts aren’t sure about the exact cause of nitrogen narcosis.

When you inhale compressed air from an oxygen tank while under a lot of pressure from water, it increases the pressure of oxygen and nitrogen in your blood. This increased pressure affects your central nervous system. But no one’s sure about the specific mechanisms that cause this to happen.

Nitrogen narcosis can affect any deep-sea diver, and most experience some of its symptoms at some point.

However, you have a higher risk of developing nitrogen narcosis if you:

  • drink alcohol before diving
  • have anxiety
  • are fatigued
  • develop hypothermia before or during your dive

If you’re planning a deep-sea dive, make sure you’re well-rested, relaxed, and properly dressed before attempting any dive. Avoid drinking alcohol beforehand too.

Nitrogen narcosis usually happens in the middle of a deep-sea dive, so it’s rarely diagnosed by a doctor. Instead, you or your diving partner will likely notice the symptoms first. Make sure that those around you during your dive are aware of the condition and how to recognize its symptoms, in both themselves and others.

Once you reach a boat or land, seek emergency treatment if your symptoms aren’t going away after a few minutes.

The main treatment for nitrogen narcosis is simply getting yourself to the water’s surface. If your symptoms are mild, you can stay in shallower waters with your dive partner or team while you wait for them to clear. Once your symptoms have cleared, you can resume your dive at that shallower depth. Just make sure you don’t return to the depth where you started having symptoms.

If your symptoms don’t resolve once you reach shallower water, you’ll need to end your dive and head to the surface.

For future dives, you may need a different mixture of gases in your oxygen tank. For example, diluting oxygen with hydrogen or helium instead of nitrogen may help. But this can also increase your risk of developing other diving-related conditions, such as decompression sickness.

Work with your doctor and an experienced diving instructor to find some other options to try for your next dive.

Nitrogen narcosis is fairly common and temporary, but that doesn’t mean it can’t have lasting effects. Some divers who develop nitrogen narcosis become too disoriented to swim to shallower water. In other cases, a diver can slip into a coma while still deep underwater.

Trying to get yourself back to the surface can also lead to complications. If you rise too quickly, you could develop decompression sickness, often called the bends. This results from a rapid decrease in pressure. Decompression sickness can cause serious symptoms, including blood clots and tissue injuries.

Seek emergency treatment if you experience the following symptoms after coming back to the water’s surface:

  • fatigue
  • appetite loss
  • headache
  • general malaise
  • tendon, joint, or muscle pain
  • swelling
  • dizziness
  • pain in the chest
  • trouble breathing
  • double vision
  • speaking difficulties
  • muscle weakness, primarily on one side of your body
  • flu-like symptoms

You can also reduce your risk of developing decompression sickness by:

  • slowly approaching the surface
  • diving on a good night’s sleep
  • drinking plenty of water beforehand
  • avoiding air travel shortly after diving
  • spacing out your dives, ideally by at least a day
  • not spending too much time in high-pressure depths
  • wearing a proper wetsuit in cold water

You should also be extra mindful of reducing your risk of decompression sickness if you:

  • have a heart condition
  • are overweight
  • are older

Make sure that you and everyone you’re diving with knows how to recognize signs of decompression sickness and how to reduce their risk of developing it.

In most cases, nitrogen narcosis clears up once you reach shallower water. But symptoms like confusion and poor judgement can make this hard to do. With a little preplanning and awareness, you can continue diving safely and reduce your risk of nitrogen narcosis and its potential complications.