Early School Start Times and Childhood Development

This content was created by the National Sleep Foundation


Why scientists want your kids to sleep in

If early weekday mornings are a battlefield at your house, it may come as no surprise that what time kids have to wake up for school is a hot topic among researchers and educators alike. Administrative concerns (such as a resistance to changing complicated and expensive busing schedules and a reluctance to pushing back sports practices—which could result in purchasing field lights) often lead to middle- and high schoolers leaving home before dawn. The result: Early school starts translate to teens getting just seven hours of sleep a night, which is far short of the nine-plus that's recommended for that age range. And these early wakeups could have lasting, negative health consequences for growing kids, robbing them of valuable sleep right when they need it the most. In fact, early school start times:

Buck Adolescent Biology

Puberty triggers a shift in teens' circadian rhythm, making it harder for them to fall asleep early and log the nine or more hours they typically need. Still, 85 percent of junior and senior high schools in the U.S. start before 8:30am—and half of those start between 7:00am and 8:00am.

Shortchange Teens of Dreams

Unfortunately, the sleep that kids lose out on when their alarms go off pre-dawn is the most valuable kind for their developing brains: rapid eye movement (REM) sleep,. Lower amounts of REM sleep (the phase in which dreams are most likely to occur) have been linked to both behavior and memory problems.

Lead to Lower Test Scores

What's, perhaps, even scarier: Weaker academic performance could lead to lower-quality jobs and lower income potential years down the road. But every little bit counts. Kids who get A's average 15 more minutes of sleep a night than kids who get B's. And the B-students average 11 more minutes than the C-students.

Leave Kids Tired and Hungry

Not getting enough sleep may also fuel the risk for obesity. Sleep deprivation is linked to an increase in ghrelin (an appetite-stimulating hormone that urges the body to eat calorie-rich food) and a decrease in leptin (a hormone that quells hunger). Add to that an increase in the stress hormone cortisol and kids are left more susceptible to weight gain, type 2 diabetes, and heart disease—serious conditions that could threaten their lives.