Carefully planning a scuba diving expedition is synonymous with both success and enjoyment in your favourite water sport. That's why the first rule to remember is that you should never dive alone - especially when venturing beyond 30 metres where dangerous situations can occur. One of the most common hazards is body poisoning or nitrogen narcosis, colloquially known as "the martini effect".
This condition occurs during deep diving due to the high solubility of the breathing gas in water, which affects the diver's consciousness. While its effects are reversible, it can cause dizziness, hallucinations and even loss of consciousness, making it essential to understand nitrogen narcosis and the precautions every diver should take.
Causes of Nitrogen Narcosis
As depth increases, so does water pressure, resulting in higher air density. This leads to respiratory stress causing our body to retain carbon dioxide - the actual cause of poisoning or intoxication.
Recent studies show that reducing nitrogen in the breathing gas mixture decreases this effect, though it hasn't been conclusively proven as the direct trigger. Other theories suggest it's caused by chemical compounds from nitrogen, carbon dioxide and pressure working in combination.
What's certain is that beyond 60 metres, the risk of nitrogen narcosis becomes highly probable.
Symptoms of Nitrogen Narcosis
It's important to clarify that narcosis is intoxication, not an illness, and therefore reversible. The effects resemble having had too many drinks, but we shouldn't underestimate the symptoms as even a single one could lead to serious accidents.
Typically, symptoms appear in this order:
- Mental impairment, with gradually slowing cognitive functions.
- Significant slowing of physical movements.
- Unexpected feelings of anxiety, carelessness or even euphoria.
- Loss of consciousness or fainting - when the situation becomes critically dangerous.
How to Avoid Nitrogen Narcosis
As with any emergency situation, following key steps prevents minor issues becoming major problems. These essential tips could prove vital:
- If you're not prepared to go beyond 40 metres, don't attempt it. Deep diving requires progressive training - don't run before you can walk.
- At the first sign of narcosis, however mild, begin your ascent. A few metres shallower will relieve pressure-related symptoms.
- Similarly, if you feel euphoric below 40 metres, ascend slightly. Understanding your mental state is crucial.
- Avoid overexertion during deep dives as physical strain increases intoxication risk.
- If everything feels unusually difficult, ascend slightly. Monitoring mental-physical coordination is key.
- And of course, every responsible diver's golden rule: never dive alone.
Theory doesn't always match practice - some divers regularly operate at 20-40 metre depths without experiencing narcosis, while others report symptoms. This depends on your physical condition, water temperature (especially cold water), blood alcohol content and other factors affecting safety margins.
By following standard diving safety protocols, you'll minimise risks. This remains the best advice any diving enthusiast can give. For those seeking extreme diving experiences along Spain's coasts, explore our directory of diving schools offering premium services.
