Many opponents of later school start times say that if schools start later, kids will simply go to bed later. According to new research, however, that’s not necessarily so.
In a national study of urban teenagers, researchers found that high school start times after 8:30 a.m. increased the likelihood that teens obtained the minimum recommended amount of sleep, benefiting their overall health and well being.
“Teens starting school at 8:30 a.m. or later were the only group with an average time in bed permitting eight hours of sleep, the minimum recommended by expert consensus,” said lead author Orfeu Buxton, associate professor of biobehavioral health at Penn State. “Later school start times were associated with later wake times in our large, diverse sample.”
Teens with the earliest high school start times — 7:00-7:29 a.m. — obtained 46 minutes less time in bed on average compared with teens with high school start times at 8:30 a.m. or later.
School start times after 8:30 a.m. were associated with increased time in bed, extending morning sleep by 27-57 minutes compared to those teens with earlier school start times.
“The presumption is if you let kids start school later they will simply go to sleep later and still not get enough sleep,” Buxton said. “But that’s a hypothetical scenario. There wasn’t data to back that up.”
While researchers did find that teens with the earliest school start times were going to bed earlier than those with 8:30 a.m. or later, the teens with earlier start times still did not get the recommended amount of sleep. Only those teens with schools that had a start time of 8:30 a.m. or later actually got the recommended amount of sleep, Buxton said.
One theory is that, despite going to bed earlier than their peers, teens with the earliest school start times didn’t get enough sleep possibly due to anticipation of an early wake time the following morning, according to Buxton.
In addition, the investigators considered other research that looked at teens’ “sleep debt,” where teens make up for lost sleep on non-school days, leading them to wake up consistently and significantly later than those on school days.