More than 15,000 students in grades 6-11 completed online surveys — about bedtime, wake time and total sleep time, as well as sleepiness during homework and academic engagement — before the start of the schedule change and then a year later.
The percentage of students who reported feeling too sleepy to do their homework declined after the later start, from 46% to 35% among middle school students and from 71% to 56% among high school students. In addition, scores on a measure of academic engagement increased for both middle school and high school students.
“The study findings are important because getting enough sleep is critical for adolescent development, physical health, mood, and academic success,” said Lisa J. Meltzer, an associate professor of pediatrics at National Jewish Health in Denver, Colorado. “Biological changes in the circadian rhythm, or internal clock, during puberty prevents teens from falling asleep early enough to get sufficient sleep when faced with early school start times. This study provides additional support that delaying middle and high school start times results in increased sleep duration for adolescents due to later wake times.”
The American Academy of Pediatrics adopted a policy statement five years ago advising middle and high schools to start school at 8:30 or later, saying the adolescent sleep-wake cycles begin to shift up to two hours later at the start of puberty. The pediatricians’ group called chronic sleep loss in children and adolescents one of the most common and easily fixable public health issues.
The American Academy of Sleep Medicine recommends middle schools and high schools should start at 8:30 a.m. or later to support teen health, alertness and safety.
Yet, a 2014 School Health Policies and Practices Study found 93% of U.S. high schools and 83% of middle schools started before 8:30 a.m.
This is one of those education issues that instigates fierce debate. Those who argue for later start times often meet admonishments that teens need to get ready for real life and that means getting up at the crack of dawn for jobs. That rebuttal is losing potency with the rise of flextime and telecommuting, especially among younger and more educated workers.