Excess post-exercise oxygen consumption Excess post-exercise oxygen consumption Excess post-exercise oxygen consumption (EPOC, informally called afterburn) is a measurably increased rate of oxygen intake following strenuous activity. In historical contexts the term "oxygen debt" was popularized to explain or perhaps attempt to quantify anaerobic energy expenditure, particularly as regards lactic acid/lactate metabolism; in fact, the term "oxygen debt" is still widely used to this day. However, direct and indirect calorimeter experiments have definitively disproven any association of lactate metabolism as causal to an elevated oxygen uptake. In recovery, oxygen (EPOC) is used in the processes that restore the body to a resting state and
Anaerobic exercise performed for longer periods of time. Activities such as walking, long slow runs, rowing, and cycling require a great deal of oxygen to generate the energy needed for prolonged exercise (i.e., aerobic energy expenditure). In sports which require repeated short bursts of exercise however, the anaerobic system enables muscles to recover for the next burst. Therefore, training for many sports demands that both energy producing systems be developed. The two types of anaerobic energy systems are: 1) high energy phosphates, adenosine triphosphate and creatine phosphate; and 2) anaerobic glycolysis. The former is called "alactic anaerobic" and the latter "lactic anaerobic"