Staying up late was very harmful to health. Long-term staying up late would affect the body's biological clock and metabolism, leading to various health problems. Staying up late until two o'clock every day may increase the risk of cardiovascular disease, obese, diabetes and other diseases. It may also affect memory, learning ability and mental health. Therefore, in order to maintain health, one should try to avoid staying up late and maintain a regular schedule and good eating habits. In addition, proper physical exercise and adequate sleep could also help maintain good health.