The main reasons for waking up at three or four o’clock in the morning include the formation of sleep habits, increased night urination leading to frequent night, mental stress. 1. Sleep habit formation: for most of the elderly, the usual sleep time is generally less than young people, if the night eight, nine o’clock to sleep, three or four o’clock in the morning to wake up, is a normal phenomenon. 2. Increased nocturia leading to frequent nighttime: the elderly with prostate disorders, chronic cardiac insufficiency patients, drink a lot of tea or beer before going to bed at night often due to frequent urination leading to frequent nighttime, easy to wake up at 3:00 a.m., 4:00 a.m.. 3. Excessive mental stress: some people may be due to different reasons in the work, study and life in the mental burden, psychological pressure is very great, resulting in long-term anxiety, depression and other situations occur, often appear in the quality of sleep decline, insomnia, can appear at three or four o’clock wake up phenomenon. Wake up at three or four o’clock for a long time, if it affects the usual work, study and life should be taken seriously, it is recommended to go to the regular hospital, according to different reasons to consult the neurology, urology, cardiology or psychiatry and other related departments.