[Research progress of the effects of high-intensity interval training on excess post-exercise oxygen consumption in...

Elevated human metabolism during recovery is associated with increased excess post-exercise oxygen consumption (EPOC). EPOC is linearly related to exercise duration and exponentially related to exercise intensity. It is commonly believed that near-maximal intensity interval training prompts the body to produce greater EPOC. This review focuses on the origin and development of high-intensity interval training (HIIT), analyzes its concept, classification and function, and discusses its effects on human EPOC. HIIT promotes a significant increase in EPOC during the fast recovery period, whereas the changes of EPOC during the slow recovery period are still inconclusive; Sprint interval training (SIT) promotes a significant increase in EPOC throughout the whole recovery period. Compared with HIIT, the body's energy expenditure and oxygen uptake (VO₂) increase significantly during moderate-intensity continuous training (MICT), but the total energy expenditure and VO₂ during exercise and 24 h of recovery period are similar between the two types of exercises, indicating that greater EPOC is generated during the recovery period of HIIT. The mechanisms by which interval training improves EPOC include increasing lung ventilation and catecholamine secretion, accelerating systemic circulation, increasing body temperature, promoting glycogen resynthesis, rapid recruitment of fast twitch muscle fibers and uncoupling of mitochondrial respiration, up-regulating hypoxia inducible factor-1 alpha and skeletal muscle protein, as well as improving intestinal flora.