The optimal time of the day for sleep varies from person to person and is related to the patient’s age, physical condition and general situation. Younger people sleep more, and adults should generally maintain 7-8 hours of sleep. Usually newborns sleep except for feeding time, after 1 week the sleep time can be shortened to 16-20 hours for newborns, 14-15 hours for infants up to 1 week old, further shortened to 12-14 hours for toddlers 1-3 years old, and usually children after 3 years old need 10-12 hours of sleep per day. For adolescents, they need to maintain 8-9 hours of sleep per day, while adults can maintain 7-8 hours of sleep per day, and for the elderly, the sleep time will be relatively shortened, generally the average sleep time is 7 hours. In addition, sleep time needs to be extended when you are tired, pregnant or sick. In daily life, you should maintain sufficient sleep time, ensure rest and avoid staying up late to benefit your health.