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
Arteriovenous oxygen difference diff. The maximum a-vO diff is also usually greater in trained athletes than in untrained individuals. This is a result of aerobic exercise leading to hypertrophy of the slow twitch muscle fibres mainly due to increased capillarisation. The increase in capillary beds in the muscle means that blood supply to that muscle can be greater and diffusion of oxygen, carbon dioxide, and other metabolites increases. With training the muscles also improve in their ability to extract oxygen from the blood and process the oxygen, possibly due to adaptations of the mitochondria and an increase in the muscle's myoglobin content. Research