Island Divers Hawaii Staff Members

A deep dive (pun intended) into the physics of nitrogen as a breathing gas and you will find a co efficient that measures the narcotic effect of the gas. How does this relate to the use of nitrox on shallow dives? What I do remember from my days as a younger open circuit technical diver hungry for information was clearly cemented in my mind by the example of nitrous oxide. That gas has a high coefficient that has measurable effects at normal atmospheric pressures. This piece of information made nitrogen narcosis, something I had never experienced, more real to me.

Regardless of whether you feel it or not, your body and brain is being effected by nitrogen the deeper you go. That’s just straight physics and not really an arguable point.  The body responds to a gas according to its partial pressure at the depth you are diving, not as the percentage in the original mix.  This explains why oxygen can become toxic when you go deep enough. Even though 100% oxygen at the surface is just fine. It also explains why the use of nitrox on shallow dives results in less nitrogen in the body.

Take Home Message about Diving Nitrox

Take home message: less nitrogen in your gas mix, i.e. nitrox, means less nitrogen goes into your body compared to the same dive on air.

So, if money is not a constraint, why not reduce the amount of nitrogen partial pressure you experience while going diving? Even if it is just a shallow dive? Some people report decreased fatigue after diving nitrox, some don’t.  But everyone that dives nitrox vs air on the same profile is putting less nitrogen into their tissues. I can tell the difference post dive in how I feel, not everyone reports that. That is pretty subjective. However, on the same dive profile, what is not subjective is that the nitrox diver put less nitrogen into their tissues that someone who dove air.