An insidious condition that gradually becomes more apparent with depth, inert gas narcosis is an aspect of diving that’s as well accepted as, say, decompression sickness but whose influence on diver safety can be even more profound.
Popularised as the “Rapture of the Deep” by scuba diving pioneer Jacques Cousteau in his 1953 book, The Silent World, some divers are mistakenly convinced that the experience is always pleasurable. It can be. Then again, it can be something frighteningly different.
Although individual tolerance levels vary enormously, narcosis will – like alcohol – affect different people in different ways. More importantly, it manages to impact on the same person in different ways on different days and at varying depths.
Faced with such uncertainties, some divers believe that their projected tolerance to narcosis is reflected in their ability to perform seemingly simple tasks at simulated depth in a recompression chamber. Mistakenly convinced that their performance in the ‘pot’ is a true measure of their susceptibility, they then undertake dives for which they’re ill-prepared.
Failing to gradually acclimatise to depth, they’ll happily hop into the ocean without giving thought to the fact that it might have been weeks, or even months, since their last deep dive.
It’s an attitude that’s remarkably similar to drink-driving in its potential for disaster, and one of the reasons why gas blends other than plain air are widely used for deeper diving. Nevertheless, there’s still no magic gas mix that will completely eliminate the unpredictable effects of narcosis, or change the attitude of that minority who remain convinced that they have never experienced the condition and that, regardless of depth, they are always in control – an outlook at odds with Cousteau’s observation that, “Intellectuals get drunk early and suffer acute attacks on all the senses, which demand hard fighting to overcome."
Diving since 1961 — with a background in military, commercial, recreational and technical diving — David Strike has dived extensively throughout the Asia-Pacific region, is a Fellow of the Explorers Club and the organiser of the biennial OZTeK Diving Conference.