Districts snooze on teen sleep Costs, outside activities and student resistance keep high schools answering the early bell: “Recent studies show that a child’s biological clock moves forward in the teen years. As a result, teenagers stay up later – often it’s 11 p.m. before they get tired – and need to sleep later and longer than previously thought. But many high schools start around 7 a.m., and their students average about 7 1/2 hours of sleep a night. Researchers say teens needs nine hours of sleep. Sleep loss has been shown to increase irritability, anxiety and depression; decrease socialization and humor; and result in hypersexuality, mental fatigue, reduced memory and an inability to handle complex tasks.”