Anaerobic glycolysis is the transformation of glucose to pyruvate when limited amounts of oxygen (O2) are available. Anaerobic glycolysis is only an effective means of energy production during short, intense exercise, providing energy for a period ranging from 10 seconds to 2 minutes. The anaerobic glycolysis (lactic acid) system is dominant from about 10–30 seconds during a maximal effort. It replenishes very quickly over this period and produces 2 ATP molecules per glucose molecule, or about 5% of glucose's energy potential (38 ATP molecules). The speed at which ATP is produced is about 100 times that of oxidative phosphorylation. The pH in the cytoplasm quickly drops when hydrogen ions accumulate in the muscle, eventually inhibiting enzymes involved in glycolosis.
The burning sensation in muscles during hard exercise can be attributed to the production of hydrogen ions during a shift to anaerobic glycolysis as oxygen is converted to carbon dioxide by aerobic glycolysis faster than the body can replenish it. These hydrogen ions form a part of lactic acid along with lactate. The body falls back on this less efficient but faster method of producing ATP under low oxygen conditions. This is thought to have been the primary means of energy production in earlier organisms before oxygen was at high concentration in the atmosphere and thus would represent a more ancient form of energy production in cells.
The liver later gets rid of this excess lactate by transforming it back into an important glycolytic intermediate called pyruvate. Aerobic glycolysis is a method employed by muscle cells for the production of lower-intensity energy over a longer period of time.
The process of converting the excess lactate back into pyruvate is known as the Cori cycle, and occurs in the liver.
Many anaerobic microorganisms carry out Anaerobic Glycolysis through Fermentation.