Anaerobic glycolysis is a metabolic process that occurs in the absence of oxygen, allowing cells to generate energy quickly. It primarily takes place in the cytoplasm of cells and involves the breakdown of glucose into pyruvate, producing a small amount of ATP (adenosine triphosphate), which is the energy currency of the cell. This process is crucial during high-intensity exercise when oxygen supply is limited. When pyruvate is produced, it can be converted into lactate (or lactic acid) in order to regenerate NAD+, a coenzyme necessary for glycolysis to continue. While anaerobic glycolysis is less efficient than aerobic respiration, it provides a rapid source of energy, making it essential for activities like sprinting or heavy lifting.