Sleep-Deprived Adolescents Circadian rhythms shift in adolescence. Adolescents tend to fall asleep later and wake up later. Few teenagers get the 8.5 to 9 hours of sleep that they need to feel fully rested. In the U.S., more than two-thirds of teenagers report that they get less than 7 hours of sleep on school nights, which is probably why they tend to sleep about 2 hours longer on weekends. Consequences of regular sleep loss include poor school performance, increased risk of accidents and injuries, and depressed mood (Colrain & Baker, 2011).