Staying up late one night occasionally will not affect life expectancy in general, but staying up late often will cause a variety of damage to the body. Staying up late is likely to cause fatigue, mental discomfort, decreased immunity, and the day after staying up late is prone to headache and brain swelling, and inability to concentrate. Staying up late for a long time can cause insomnia, forgetfulness, irritability, anxiety and other neurological and mental symptoms. Men and women of childbearing age often stay up late, which can affect fertility. Staying up late increases the pressure on metabolism, which in turn makes it easy to produce chronic diseases such as hypertension and diabetes. Overwork is prone to nervous system dysfunction, causing imbalances in the major organs and systems of the body, resulting in cardiac arrhythmias, endocrine disorders, etc. Serious cases will also lead to systemic stress, the chances of infectious diseases will increase accordingly. Staying up late is a serious health hazard and should be avoided as much as possible to develop the good habit of going to bed early and waking up early.