Starting school later may have a positive impact on important aspects of high school life. That’s the evidence from a new review of published research
The review found that teens slept about 19 minutes longer on school nights when school started up to 60 minutes later. That adds up to more than 1.5 hours of sleep during the school week.
When school started more than 60 minutes later, teens slept about 53 minutes more on school nights. That’s more than 4 hours of sleep per week.
For sleep-deprived teens, getting more sleep could be life-saving. The review found that teen car crash rates were lower when school started later.
Starting school later also may benefit teens in other ways. The review found that later school start times may reduce tardiness or absences from school. Teens also may feel less depressed when school starts later.
Results are published in the Dec. 15 issue of the Journal of Clinical Sleep Medicine.
It’s clear that many teens are desperate for more sleep. The American Academy of Sleep Medicine recommends
that teens sleep 8 to 10 hours nightly for optimal health. Yet CDC data
show that about 69 percent of high school students sleep less than 8 hours on an average school night. That’s why the National Healthy Sleep Awareness Project launched the “Sleep Recharges You
Biology and school start times may share the blame for teen sleep loss. The AASM reports that a natural shift in the timing of the body’s internal “circadian” clock occurs during puberty. As a result most teens have a biological preference for a late-night bedtime. This makes it hard for night owl teens to become early birds for school.
In a 2014 policy statement
, the American Academy of Pediatrics recommended that middle and high schools delay the start of class to 8:30 a.m. or later. A 2015 analysis
by the CDC found that U.S. high schools start class at an average time of 7:59 a.m. Only 14 percent of high schools started at 8:30 a.m. or later.
The AASM encourages
parents and local school boards to work together to implement high school start times that allow teens to get the healthy sleep they need.