Abstract
Since various functions of the body have their own biorhythms adapted to the living environment, it is considered that the reactivity of physical locomotion may vary depending on the time of day when exercise is performed. In this study, in order to assess differences in locomotive capacity according to the time of day, 18 male high school baseball players were tested for physical strength in the morning (8: 00) and evening (18: 00). Furthermore, the time differences in endocrine and metabolic responses after physical exercise were assessed according to biorhythms. (1) Physical capacity changed according to the time of evaluation, and was greater in the evening than in the morning. (2) Among physiological functions that determine the development of physical strength, thyroid-stimulating hormone (TSH) and growth hormone glasma levels were higher after evening exercise than after morning exercise. (3) The increase in urinary excretion of 3-methylhistidine (degradation index of muscle protein) after exercise was smaller in the evening than in the morning. These findings suggest that evening exercise promotes the development of physical strength more than morning exercise.
