UW study: Teens get more sleep, better grades with later start times

Seattle teenagers are getting more sleep and better grades since they started going to school later in the day, according to a new study by the University of Washington.

Despite a logistical challenge, secondary schools, including all 18 highs schools and most middle schools, in Seattle shifted their start times from 7:50 a.m. to 8:45 a.m. in fall 2016. According to the UW study, teenagers shifted their wake-up times by about 34 minutes each night (median).

The teens involved in the study at two high schools are now sleeping an average of seven hours and 24 minutes, as compared to six hours and 50 minutes before start times were pushed later. It’s recommended teens get about 10 hours of sleep each night.

“This study shows a significant improvement in the sleep duration of students — all by delaying school start times so that they’re more in line with the natural wake-up times of adolescents,” senior and corresponding author Horacio de la Iglesia, a UW professor of biology, said in a news release.

Students in the study wore wrist monitors to track light and activity data. The results showed that teens slept in, rather than staying up later.

The study also revealed grades improved 4.5 percent. The number of tardies and first-period absences decreased at one of two schools involved in the study.

Research has shown that circadian rhythms of adolescents are different than those of adults. Disrupting teen sleep has severe consequences, according to UW’s research, including to mental health.

“To ask a teen to be up and alert at 7:30 a.m. is like asking an adult to be active and alert at 5:30 a.m.,” said de la Iglesia.

The American Academy of Pediatrics has recommended that middle and high schools start classes no earlier than 8:30 a.m.

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