It is better to run for half an hour every day or in the morning. Running at night can promote the body to sweat and lose weight, while running in the morning can easily lead to respiratory diseases and joint pain. Running at night is better than running during the day. In the city, it is not suitable for running in the morning, and the air is very dirty in the morning. When running, due to the increase of breathing volume, more harmful substances will be inhaled, which is prone to respiratory diseases. In addition, when running in the morning, the moisture in the air is heavy. When the body sweats a lot, the pores open a lot and moisture can enter, causing joint pain. In addition, most people run on an empty stomach in the morning, because hypoglycemia is easy to occur. After a day's study and work, the spirit is in a state of exhaustion, which is more suitable for running to relieve mental stress. Proper running helps to improve the quality of sleep at night. In addition, the air is dry at night. However, the running time at night should not be too long. When you are tired, you should not run again, so as not to affect your sleep. You can't ignore keeping warm during exercise, otherwise it will easily cause a cold. When the weather is cold, you can warm up before you start exercising. You don't need to take off your clothes immediately, but you can also avoid taking off your clothes when sweating, which will cause a cold.