We all need sleep. It’s a core part of being human, consuming up to a third or more of each day. Without sleep, basic brain processes like attention and memory, the ability to learn, and our overall well-being go haywire. But over the past century, the average amount of sleep for American school-aged children and adolescents has dropped by about 1 hour to just under 7 hours.
This lost hour hits teenagers the hardest, and the detrimental effect of sleep deprivation on the physical and mental health of teenagers has been extensively studied. This is because adolescence is a time filled with all sorts of bodily changes, increased independence, and the emergence of new social roles—all affecting health and behavior. Bedtimes naturally become later with each passing year as a teen grows older. On the other hand, rise times, which are more often determined by school start times, remain unchanged.
Along these lines, a simple intervention has been proposed to increase teen sleep—delay school start times. In the US, this proposal has been backed by the CDC, which issued a statement in 2018 proposing that start times be moved to 8:30 or later. This concept has been tested in various settings. Several school districts in the US and around the world have indicated that changing school start times changed teen sleep. For example, a study in one Rhode Island School District that transitioned from a 08:25 a.m. start time in ninth grade to a 7:20 a.m. start time in 10th grade confirmed a shortening of daily sleep of approximately 20 min. In Singapore, a recent study showed that a delay of 45 min in start times in one all-girls high school resulted in a modest (about 10 minutes) increase in daily sleep.
