April 27 (UPI) -- Schools may be closed across much of the United States because of the COVID-19 pandemic but, when they re-open, a later start to the day could help students get the sleep they need to perform better, according to a new study.
The analysis, published Monday in JAMA Pediatrics, found that adolescents and teens at two high schools that delayed the school day by an hour had around 40 minutes more sleep per night and needed less extra sleep on the weekends compared to those at schools that opened earlier in the morning.
"Most teens require a lot of extra sleep on weekends to payback the 'sleep debt' they run up during the school week," co-author Dr. Rachel Widome, an associate professor of epidemiology and community health at the University of Minnesota, told UPI. "In our study we observed that students in schools that shifted to a later start time did not need to do as much catch-up sleep on weekends, indicating they were less sleep-deprived during their school week."
The American Academy of Sleep Medicine recommends that young people between 13 and 18 years old get eight to 10 hours of sleep each night. Data from the U.S. Centers for Disease Control and Prevention, however, suggests that roughly 60 percent of adolescents and teens sleep sufficiently on school nights.
This lack of sleep has been linked with declines in academic performance, as well as mental and physical health problems. It also impacts behavior and mood, Widome said.
For the study, researchers assessed sleep times among more than 450 students at five high schools in the Minneapolis-St. Paul area. All five of the schools opened each day at 7:30 or 7:45 a.m. as of 2016, but two of the schools modified their start times in 2017, opting to start the school day 50 and 65 minutes later, respectively.
The researchers used a device called wrist actigraphy to measure sleep duration, timing and quality. The study population was roughly evenly distributed by gender, and mean age of the participants was approximately 15 years.
The team found that students who attended delayed-start schools had an additional mean of more than 40 minutes of sleep each night, and that delayed start times were not associated with falling asleep later on school nights. In addition, students attending these schools had a mean change in weekend night sleep of -24 to -34 minutes over the course of the study.
"You might think that when schools start later, any benefit would be canceled by teens compensating by just going to bed later, but that's not what we observed," Widome said. "Students in the later starting schools went to bed at a similar time as students in the early starting schools."
This reflects adolescents' hard-wired circadian rhythms, she added. Teens are ready for sleep at around 11 p.m. at night and typically struggle to wake before 8 a.m., and educators are beginning to recognize this issue, as evidence by recent law in California, which mandates that high schools open no earlier than 8:30 a.m. each day, according to Widome.
"These policies can be deployed across U.S. communities and have the potential to positively impact students from a variety of racial, ethnic and economic backgrounds," she said.