Schools want to improve student performance, 1 they may be stopping them from learning. Teenagers need 8.25 to 9.5 hours of sleep per night. But, most are not getting that much. However students study hard, they are too tired to learn effectively.Teenagers may go to bed early,4 they have problems falling asleep Teenagers should naturally wake up after 8. 5 , schools start earlier than that. Unfortunately, 6 the evidence for starting lessons later is strong, many schools will not do it.