Fitness has the best effect on muscle growth during the period of 4-6 pm. During this period, the proportion of testosterone and cortisol is the largest, which is most conducive to human muscle synthesis, that is, muscle gain! Testosterone level represents the level of muscle growth, while cortisol will affect muscle synthesis and even decompose muscle. The human body temperature is the highest around 4-6 pm, which is equivalent to passive warm-up, muscle viscosity becomes smaller, resistance becomes smaller, and natural force is more convenient. Make the elastic tissue of muscle more elastic and not easy to fracture. During this period of training, the chances of injury will be much smaller than at other times. At four o'clock in the afternoon, the maximum strength of muscles will also reach its peak. Scientists compared the exercise ability of the subjects at different times and found that the muscle strength and explosive force in the afternoon were better than that in the morning. At night 17- 19, all the functions of human body are in the best state, and physical fitness and oxygen uptake reach the peak. In addition, hormones and enzymes in the body are also in the best state, and various senses such as vision, touch and smell of the human body are in their heyday, so exercise at this time is more conducive to health and the exercise effect is better. 20: 00 -22: 00 If you belong to white-collar workers who get off work late, or people who want to go to the gym after dinner, you can choose this time period from 20: 00 to 22: 00. Generally, this time period is 1-2 hours after dinner and 1-2 hours before going to bed, which will neither affect digestion nor sleep.