Normoxic is the name given to a breathing gas mix for which the percentage or fraction of oxygen is similar to the one of air, but contain a different mix of other gases. Along with hypoxic and hyperoxic, normoxic is one of the three kinds of breathing gas mixes for diving.


Hyperoxic is a term used for breathing gases that has a higher percentage or fraction of oxygen than regular air. The term or word is not so commonly used because of the designation Nitrox or Enriched Air, which is used instead to cover hyperoxic gases. It is the opposite of hypoxic.

WOB – work of breathing

The work of breathing or WOB is in simple terms, the effort required by the lungs to breathe. But to be more accurate it refers to the energy expended to inhale and exhale a breathing gas. The WOB is usually expressed as work per unit volume.