Scientists generally recommend teenagers get eight to 10 hours of sleep each night. Early-morning social obligations, such as school start times, force them to either shift their sleep schedule earlier or worse, cut it short.
According to a survey of youths in 2017 by the US Centers for Disease Control and Prevention, only one in four high school students reported sleeping the minimum recommended eight hours each night.
“All of the studies of adolescent sleep patterns in the US are showing that the time at which teens generally fall asleep is biologically determined,” said Given Dunster, a University of Washington (UW) doctoral student in biology.
“But the time at which they wake up is socially determined. 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.”
Dunster and a group of researchers at UW and the Salk Institute for Biological Studies released a study on 12 December that showed later school start times boosted students’ total nights’ rest to seven hours and 24 minutes. When schools start earlier, students only had a median of six hours and 50 minutes a night.
The paper was a study on Seattle Public Schools reorganisation of school start times which begun in the fall of 2016. It had taken the school a year to deploy the shift: elementary schools started earlier; most middle schools and all 18 high schools shifted from 7.50am to 8.45am.
“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 time of adolescents,” said corresponding author Horacio de la Iglesia, a UW professor of biology.
“To ask a teen to be up and alert at 7.30am is like asking the adult to be active and alert at 5.30am.”
Besides getting the much-needed extra rest, it was also found that students’ academic performance improved. Final grades for their biology class were reported to be 4.5% higher for students who started school later compared with those who started earlier.
In addition, the number of late-coming cases and first-period absences declined.
The American Academy of Pediatrics recommended in 2014 that middle and high schools begin instruction no earlier than 8.30am.
And in 2018, according to Science Daily, California lawmakers nearly enacted a measure that would ban most high schools from starting class before 8.30am.