The Early Bird Gets the Bad Grade, Nancy Kalish notes:
Research shows that teenagers’ body clocks are set to a schedule that is different from that of younger children or adults. This prevents adolescents from dropping off until around 11 p.m., when they produce the sleep-inducing hormone melatonin, and waking up much before 8 a.m. when their bodies stop producing melatonin. The result is that the first class of the morning is often a waste, with as many as 28 percent of students falling asleep, according to a National Sleep Foundation poll. Some are so sleepy they don’t even show up, contributing to failure and dropout rates.
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In 2002, high schools in Jessamine County in Kentucky pushed back the first bell to 8:40 a.m., from 7:30 a.m. Attendance immediately went up, as did scores on standardized tests, which have continued to rise each year. Districts in Virginia and Connecticut have achieved similar success. In Minneapolis and Edina, Minn., which instituted high school start times of 8:40 a.m. and 8:30 a.m. respectively in 1997, students’ grades rose slightly and lateness, behavioral problems and dropout rates decreased.Later is also safer. When high schools in Fayette County in Kentucky delayed their start times to 8:30 a.m., the number of teenagers involved in car crashes dropped, even as they rose in the state.