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
Aerobic conditioning able to diffuse more oxygen into their blood than they previously could. Although exercising at lower intensities will improve aerobic conditioning, the most rapid gains are made when exercising close to an individual's anaerobic threshold. This is the intensity at which the heart and lungs can no longer provide adequate oxygen to the working muscles and an oxygen debt begins to accrue; at this point the exercise becomes anaerobic. Anaerobic training intensity for most individuals will be <85-92% of maximum heart rate. Once improvement in aerobic conditioning is apparent, for example in metabolism and oxygen uptake, the body will progressively