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 of oxygen absorbed by the body is at 6 pm; Heart beating and blood pressure regulation are most balanced between 5 pm and 6 pm, while the body's sense of smell, touch and vision are also most sensitive between 5 pm and 7 pm. So, on the whole, the effect of exercise at night is better.

After a day of exercise in the middle of the night, the human body is in a state of fatigue and needs to recover from sleep. During this period of time, exercise will aggravate physical fatigue, and it will not get the proper exercise effect, and it will increase the burden on the heart, excite the sympathetic nerve and hinder sleep.