The effect of muscle molecular clock on signaling of sports performance adaptations

Background and purpose: Physiological and behavioral processes of almost all organisms depend on the time of day. In mammals, light enters these processes in the suprachiasmatic nucleus of the hypothalamus, which forms the body's central clock, and synchronizes the body's functions with the 24-hour cycle of light and darkness. he does. In addition to perceptual and cognitive aspects of performance, circadian rhythms affect many aspects related to physiological performance such as muscle strength and flexibility. There is also a strong relationship between physical performance and (circadian) changes in body temperature, with optimal physical performance coinciding with peak body temperature in the early evening. The circadian clock, which is responsible for the circadian rhythm, exists in almost every cell, and its disruption leads to many diseases such as type 2 diabetes and metabolic syndrome. The findings show that skeletal muscle homeostasis may be disrupted not only due to lack of exercise and low dietary protein intake, but also due to disruption of circadian rhythm conditions such as continuous night work, shift work, lack of sleep, and jet lag.
Materials and Methods: In this review study, articles related to the subject were selected and studied from published texts and authoritative sites using keywords muscle molecular clock, exercise performance, circadian rhythm, and phenotype.
Results: The time of sports activities is very important in performance. Despite the timing of the activity, individual preference for doing the activity in the morning or in the evening can be a very important factor on performance. According to the reviewed studies, most of the sports performance such as strength, speed, endurance, accuracy, recovery ability, harmony, etc., were better in the evening and early night in the athletes of different team and individual disciplines. This superiority in the evening can be attributed to body temperature, hormone release, circadian rhythm, rest and recovery, etc. In some cases, such as swimming, strength and endurance are better in the morning.
Conclusion: Based on the information collected in this review study, biological and physiological rhythms have an effect on people's physical performance. Despite individual differences and personal preferences in determining training hours, taking into account a specific training time each day and training at the beginning of the day can improve people's performance. Higher body temperature in the evening, increasing the level of secretion of hormones such as cortisol and testosterone, etc. can be one of the factors affecting the better performance of athletes in the evening. But depending on the type of activity, skill level, gender of the athletes and individual differences, the time to perform the activity for better performance can vary. In addition to the mentioned cases, individual preference to perform activities during the day or night is an important factor in improving performance.
Conclusion: Based on the information collected in this review study, biological and physiological rhythms have effect on people's physical performance. Despite individual differences and personal preferences in determining training hours, by considering a specific training time each day and training at the beginning of the day, people's performance can be improved.