Anaerobic glycolysis is an energy system that uses:

The two types of anaerobic energy systems are- high energy phosphates, adenosine triphosphate and creatine phosphate; and - anaerobic glycolysis. The former is called alactic anaerobic and the latter lactic anaerobic system. Highenergy phosphates are stored in limited quantities within muscle cells.

The higher you go up the less oxygen there is