VO₂ max is the maximum (max) rate (V) of oxygen (O₂) your body is able to use during exercise.

Oxygen is a critical ingredient in the respiratory process that’s involved in breathing. As you breathe in oxygen, your lungs absorb and turn it into energy called adenosine triphosphate (ATP)Trusted Source.

ATP powers your cells and helps release the carbon dioxide (CO₂) that’s created during your respiratory process when you exhale.

The benefits are simple: The greater your VO₂ max, the more oxygen your body can consume, and the more effectively your body can use that oxygen to generate the maximum amount of ATP energy.