Nitrox Gear

Nitrox refers to any gas mixture composed (excluding trace gases) of nitrogen and oxygen; this includes normal air which is approximately 78% nitrogen and 21% oxygen, with around 1% inert gases, primarily argon. The most common use of nitrox mixtures containing higher than normal levels of oxygen is in SCUBA diving where the reduced percentage of nitrogen is advantageous in reducing nitrogen take up in the body's tissues and so extending the possible dive time and/or reducing the risk of decompression sickness (also known as the bends).

Nitrox is mainly used in scuba diving to reduce the proportion of nitrogen in the breathing gas mixture. Reducing the proportion of nitrogen by increasing the proportion of oxygen reduces the risk of decompression sickness, allowing extended dive times without increasing the need for decompression stops. Nitrox is not a safer gas than compressed air in all respects: although its use reduces the risk of decompression sickness, it increases the risk of oxygen toxicity and fire.

It is generally untrue that breathing nitrox can reduce the effects of nitrogen narcosis, as oxygen seems to have equally narcotic properties under pressure; thus one should not expect a reduction in narcotic effects due only to the use of nitrox. For a reduction in narcotic effects Trimix gases which also contain helium are generally used.

There is anecdotal evidence that the use of nitrox reduces post-dive fatigue, particularly in older and or obese divers; however the only known double-blind study to test this found no statistically significant reduction in reported fatigue. There has, however, been some suggestion that post dive fatigue is due to sub-clinical decompression sickness (DCS) (i.e. micro bubbles in the blood insufficient to cause symptoms of DCS); the fact that the study mentioned was conducted in a dry chamber with an ideal decompression profile may have been sufficient to reduce sub-clinical DCS and prevent fatigue in both nitrox and air divers.