The best time for bodybuilding is autumn morning-when the climate is cool and the air is fresh. Morning and evening should be avoided in winter, so the morning before breakfast every day is the best time to exercise and lose weight during the peak period of surface air pollution. Because exercise before meals can improve the metabolic rate in the body, the metabolic rate is still at a high level after the exercise stops. The best time to continuously consume body heat and sugar to improve body shape is childhood, and the best time to improve body shape is 1 year. Because of the vigorous metabolism and energy during this period, supplementary research found that high-intensity exercise can be carried out two hours after meals; Moderate exercise should be arranged one hour after meals; It is most reasonable to do light exercise within half an hour after meals. According to this, several optimal exercise periods can be deduced: morning period: from morning to morning before breakfast; From one hour after breakfast to the afternoon before lunch; From one hour after lunch to the night before dinner; From one hour after dinner to before going to bed. Exercise in each period has advantages and disadvantages. For example, in the morning, when the human body performs strenuous exercise, it can excite the sympathetic nerve. This rapid change will cause a series of changes in the body, affect the mental state of the whole day, and be harmful to health. In addition, at this time, blood sugar is at a low level, and exercise consumes a lot of blood sugar, which easily leads to hypoglycemia. Exercise in the morning and afternoon is influenced by objective factors such as going to work, work and housework. Modern sports physiology research shows that the highest and lowest points of human physical strength are controlled by the "biological clock" of the human body and generally reach the peak in the evening. For example, the lowest point for the body to absorb oxygen is: 00pm；; Heart beating and blood pressure regulation are most balanced between: 00 and: 00, while the body's sense of smell, touch and vision are also most sensitive between: 00 and: 00. So, on the whole, the effect of exercise at night is better. In addition, the activity of hormones in the body is also in a good state between: 00 pm and: 00 pm, and the physical adaptability and nerve sensitivity are also the best. Therefore, experts advocate evening exercise, but in the evening time, we should pay attention to the intensity of exercise, otherwise too high intensity will excite sympathetic nerves and hinder sleep.