We can all relate to the dreaded early morning alarm, and the oh-so tempting snooze button.  Sufficient sleep is critical for health, cognitive function, and overall quality of life. Chronic sleep deprivation can be detrimental to physical health, behavior and mental wellbeing at any stage of life, and especially in adolescence. To make things worse, the onset of puberty lengthens the biological clocks of teens, decreasing sensitivity to light in the morning. Adolescents are predisposed to later sleeping times, but are still expected to wake up early in the morning for class. The national Youth Risk Behavior Survey of 2007 surveyed 12,154 high school students across the US and reported 68.9% of students getting an insufficient amount of sleep (less than 7 hours of sleep per night).

Scientists from the University of Washington are working with high schools in Seattle to address this growing problem. Start times for 2 different high schools were moved approximately 1 hour later (from 7:50 am to 8:45 am). The study used wrist activity monitors to record the sleep-wake cycles of approximately 90 students, before and after the change in school start time. The wrist monitors were worn by the students all day for a period of two weeks, and recorded  light and motion data every 15 seconds – this was used to determine when the students were awake or asleep.

Scientists found that a delayed school start time resulted in a 34 minute increase in the median sleep duration ; students went to sleep around the same time each night, but slept in longer. This was associated with an increase in grades and attendance; however only one semester of first period biology class was considered, and the improvement in attendance was only observed for one of the schools with more economically disadvantaged students. Interestingly, the 55 minute delay in start time did not result in a 55 minute gain in sleep time, suggesting that there are additional factors delaying bedtime. It would be interesting for future experiments to include interventions addressing evening screen time, which is known to negatively impact sleep quality. It would also be important to evaluate any potential improvements in physical and mental health.

Managing Correspondent: Jeremy Gungabeesoon

News Article: Teens get more sleep with later school start time, researchers find. ScienceDaily

Original Article: Sleepmore in Seattle: Later school start times are associated with more sleep and better performance in high school students. Science Advances

Image Credit: dreams.co.uk