Health & Wellbeing

Two-year study finds later school start times improve student sleep

Two-year study finds later sch...
The University of Minnesota study found pushing school start time later to around 8.30am increased student sleep times by over 40 minutes each night
The University of Minnesota study found pushing school start time later to around 8.30am increased student sleep times by over 40 minutes each night
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The University of Minnesota study found pushing school start time later to around 8.30am increased student sleep times by over 40 minutes each night
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The University of Minnesota study found pushing school start time later to around 8.30am increased student sleep times by over 40 minutes each night

Over half of US teenagers sleep less than seven hours each night, and there is increasing evidence these adolescent sleep deficits affect everything from general health to academic performance. A new study, led by researchers from the University of Minnesota, followed hundreds of students across five high schools for two years and found later school start times increase overall sleep durations.

For nearly a decade now many researchers have been pushing for later school start times in the United States. Back in 2014, the American Academy of Pediatrics recommended middle and high schools start no earlier than 8.30am, yet a study published that same year found over 90 percent of US high school students started before that time.

Around eight hours of sleep every night is the general recommendation for healthy adults, however, teenagers need a little more than that. The various biological changes going on in a growing adolescent body result in wonky circadian rhythms. Teenagers generally become sleepy much later in the evening than adults, plus, they need between eight and ten hours to maintain optimal physical and cognitive health.

In this new study, a US research team offers the most comprehensive investigation conducted to date into the sustained relationship between later school start times and teenager sleep quality. The study began by recruiting 455 grade nine students from five high schools. At the beginning of the study in 2016, two of the schools pushed back their start times, by 50 and 65 minutes respectively, while the other three continued with the regular 7.30am start time.

At the end of the two-year study the results revealed those students at schools with later start times experienced an average of 43 minutes more sleep than their early-starting peers. This extension in sleep duration is important, because the primary argument often waged against later school start times is the suggestion students would simply stay up later into the night if school started later in the morning.

In fact, the study found no relative difference in sleep onset times between the early and late school starters, across the entire two year study period. So on average, teenagers went to sleep at the same time regardless of starting school at 7.30am or 8.30am.

“Furthermore, concurrent with the increase in school night sleep duration, those attending delayed-start schools had a decrease in weekend night sleep duration, suggesting lesser accumulated sleep debt with the later start times,” the researchers write in the study. “Sleep fragmentation, sleep efficacy, and sleep latency onset appeared to be minimally affected or unaffected by the shift to a later start time.”

Unlike some smaller prior studies, this new research did not examine any effects of the school start time intervention beyond overall sleep duration. So although there is prior evidence more sleep in adolescents can lead to improved academic performance, this new study is not built to address that effect.

In an accompanying editorial discussing the study, pediatric researcher Erika Cheng and JAMA Pediatrics associate editor Aaron Carroll point out the study offers significant and robust evidence that delaying school start times can result in better adolescent sleep duration. Cheng and Carroll, who did not work on the new study, refer to a notable volume of research linking mental health problems and poor academic performance in teenagers to insufficient sleep duration.

“We often blame adolescents for their not getting enough sleep, but much of that is not their fault - it is ours,” the pair of researchers write in the editorial. “We set the school start times, mostly to fit our work schedules. Pushing back school start times might be inconvenient. but it is a mutable, cost-effective, population-level strategy that would improve the lives of many, if not most, adolescents in the United States.”

The new research was published in the journal JAMA Pediatrics.

4 comments
AryehZelasko
This might come as a surprise to some people but we no longer live on farms. Most school and business hours are set around the idea that everyone is getting up at first light to feed the cows and chickens and went to sleep with the sunset.
D[]
As an educator this is an interesting study. However, I wonder about some of the additional factors. How many of those in the study are as physically active as recommended? I know that athletes who participate in early morning work-outs before school also perform better, in general, in academics. Why are we so quick to move school start times back instead of increasing physical exercise? An 8:30am start time might not seem like a big deal, but it scoots the end of day back by anywhere from 60 to 75 minutes (in the school systems I worked). That means that athletics or activities practices start at 4:00 instead of 3:00. So your average after-school practice event now runs from 4-6pm. If you are a limited practice space program (volleyball, basketball, swimming, softball, baseball, etc) your double practices run 4-6 (JV or girls/boys) and 6-8 (Varsity or boys/girls). And if you are one of many schools with limited facilities you have to figure out how to get four practices in one gym. 4-5:30, 5:30-7, 7-8:30, 8:30-10. After school theater, debate, dance, etc... groups run an hour later also. Its just something to consider when discussing 8;30am or 9am start times.

Also, truancy becomes a bigger issue in high school. Most parents are out of the house at work or on the way to work by 8:00am. My experience and anecdotal observation tells me that a teen without a parent at home to wake them up and get them out the door is less likely to make it to school that day.

I think we need to consider sleep when setting up school schedules, but we should also not be under the impression that this will not create additional problems. We need to move away from traditional schooling systems as it is. Maybe we can start by rescheduling schools so that some start early and some start late, some accelerate through grade levels by showing summative proficiency while others are able to develop foundational skills without the social pressure of matriculation. Schools are far more than 6 or 7 classes a day for four years and we need to recognize that simple solutions never are.
Signguy
This is BS; I never had trouble getting up in the morning because I went to sleep at the proper time to get enough rest, usually 10. Even movies didn't keep me up, & there was no way to record in the 60's.
guzmanchinky
This is another reason for online school. I think we will try this with our daughter, since she really wants to.