Anaerobic

Anaerobic is a term in biology that denotes something pertaining to the absence of free oxygen. Anaerobic organisms do not require oxygen for their life processes, in fact oxygen is toxic to many of them. Most anaerobic organisms are bacteria or archaeans.

An exercie is also said to be anaerobic which is neither intended to improve nor actually improves the efficiency of the body's cardiovascular system in absorbing oxygen in the body or transporting to other systems invoving other parts of the body.