How is nitrogen narcosis defined?

Nitrogen narcosis is defined as the intoxicating effect of nitrogen when it is exposed to increased partial pressure, which commonly occurs during deep dives. As a diver descends, the pressure around them increases, causing the nitrogen that is absorbed into the body to become more concentrated. This elevation in nitrogen levels can affect the central nervous system, leading to a range of symptoms similar to those of alcohol intoxication, such as impaired judgment, diminished motor skills, and altered perceptions.

The phenomenon is particularly significant at depths greater than approximately 30 meters (100 feet), where the effects may become more pronounced. Understanding nitrogen narcosis is critical for divers, as recognizing its symptoms can be essential to ensuring safety and making informed decisions while underwater.

The other options refer to conditions or scenarios that do not accurately describe nitrogen narcosis. For instance, asphyxiation underwater involves a lack of oxygen, which is different from the intoxicating effects of nitrogen. Diving while tired might impact a diver's performance but is not a definition of nitrogen narcosis. Loss of consciousness, while a possible extreme outcome of severe narcosis, is not the defining characteristic of the condition itself.