ABSTRACT
Circadian rhythms have been shown to regulate several physiological functions including body temperature, sleep/wake cycle, physical activity, and cognition. These functions are controlled by circadian clock genes, and the circadian clock system in the body is classified into two clocks which are the central clock in the suprachiasmatic nucleus (SCN) of the hypothalamus and peripheral clocks in peripheral tissues such as the liver and skeletal muscle. Therefore, many researchers are conducting basic and applied research on the relationship between circadian rhythm in peripheral tissues and physiological functions including sports performance and effects of acute exercise and exercise training. On the other hand, it has been shown that abnormal circadian rhythms and disturbance of circadian rhythms can lead to the development of several diseases such as diabetes, cancer, sarcopenia, depression, and dementia. Thus, it is also important to regulate individual circadian rhythm by considering for timing of exercise and daily physical activity. Exercise and physical activity are found to have an influence on circadian rhythms regulation (Chrono-exercise) and accumulate evidences between timing of exercise and health outcomes. This review aims to introduce evidence for chrono-exercise and suggests the importance for considering the timing of exercise and physical activity.