How long you sleep is healthy.

Theoretically, the average sleep time of newborns is about 18-20 hours a day. The best sleep time for teenagers should be 9 hours and 45 minutes.

Adults usually sleep for 7-9 hours.

The requirement of human body for sleep is that young adults usually sleep 7-9 hours every night, children and adolescents increase 1-3 hours, and the elderly decrease 1-3 hours, which is the requirement of different age groups for sleep amount (time).