In a paper published Dec. 12 in the journal Science Advances, researchers at the University of Washington and the Salk Institute for Biological Studies announced that teens at two Seattle high schools got more sleep on school nights after start times were pushed later — a median increase of 34 minutes of sleep each night. This boosted the total amount of sleep on school nights for students from a median of six hours and 50 minutes, under the earlier start time, to seven hours and 24 minutes under the later start time.
“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,” said senior and corresponding author Horacio de la Iglesia, a UW professor of biology.
The study collected light and activity data from subjects using wrist activity monitors — rather than relying solely on self-reported sleep patterns from subjects, as is often done in sleep studies — to show that a later school start time benefits adolescents by letting them sleep longer each night. The study also revealed that, after the change in school start time, students did not stay up significantly later: They simply slept in longer, a behavior that scientists say is consistent with the natural biological rhythms of adolescents.
“Research to date has shown that the circadian rhythms of adolescents are simply fundamentally different from those of adults and children,” said lead author Gideon Dunster, a UW doctoral student in biology.
“All of the studies of adolescent sleep patterns in the United States are showing that the time at which teens generally fall asleep is biologically determined — but the time at which they wake up is socially determined,” said Dunster. “This has severe consequences for health and well-being, because disrupted circadian rhythms can adversely affect digestion, heart rate, body temperature, immune system function, attention span and mental health.”
Read the full article by James Urton on UW News.