Later School Day Start Times Benefit Teens, but Adults Must Pay the Price

There's a world of difference between 7:50 a.m. and 8:45 a.m.

It’s no longer up for debate that high school start times in America are far too early. But as powerful as the evidence is that these early starts are detrimental to the health of teens, most of America still refuses to let them sleep in. If you ask the authors of a new Science Advances paper, showing concrete evidence that later school start times benefit teens, they’ll tell you it’s a persistent problem — but one that has more to do with economics than with public health.

From a medical perspective, it’s clear that early start times are bad for youth. The American Academy of Sleep Medicine and the American Academy of Pediatrics have both issued policy statements urging schools to consider pushing back start times to 8:30 a.m. or later. But despite these warnings, 93 percent of high schools still start before 8 a.m., according to a CDC report from 2014. Horatio De La Iglesia Ph.D., first author of the new paper, tells Inverse that there are two major reasons that school districts and even some parents are hesitant to start their days a little later.

“There are two issues,” he tells Inverse. One is this misperception that teenagers are lazy, they want to sleep in and if you let them wake up later by delaying school start time you’ll make them more lazy. The fact is, that we didn’t find that.”

Seattle Washington public schools
In 2017, the Seattle School District pushed school start times back by 55 minutes 

In the study, De La Iglesia, a professor of biology at the University of Washington, used the Seattle public school system, which already had plans to try out later start times, for a natural experiment. For the 2016-2017 school year, the Seattle School District pushed high school start times from 7:50 a.m. to 8:45 a.m. Over that period, De La Iglesia recruited 178 sophomores from two schools and monitored their sleep patterns, attendance, and grades in biology class.

When he monitored their sleep patterns using actiwatches (wearables that monitor sleep patterns), he found that teens slept roughly 34 minutes more each night compared to the 2016 school year. More importantly, once the change was implemented, the students began performing better in class: At the end of the school year, there was a 4.5 percent increase in the median grade in students from both schools.

Though previous studies had shown similar results, an important difference in De La Iglesia’s study is that it addresses the role of socioeconomic factors.

One of the schools involved in the study, Roosevelt High School, had far fewer “economically disadvantaged” students, to use the paper’s words. Franklin High School, meanwhile, was not as well off. This disparity was linked to a pronounced difference in the impact that later start times had on kids. At Franklin, a later start time resulted in students missing roughly two fewer school days than normal. At the more affluent Roosevelt, meanwhile, the later start time wasn’t associated with any significant change in absences or lateness.

“We don’t know the cause. We think it might be related to how they get to school. But the difference between the two schools is very clear,” says De La Iglesia.

science advances
Students at Franklin High missed fewer days of school when the start time was pushed back 

De La Iglesia is well aware that changing a school start time isn’t easy for anyone involved. In addition to changing the schedules of parents and teachers, it took a lot of convincing to get school boards to reorganize athletic practice times and school bus schedules to accommodate the change.

“The stakeholders have to deal with the consequences of the change,” he says. “There’s a little bit of, ‘We’re good as we are. Why do we need to change?’ But there are some economic consequences. Seattle had to add some school buses to the system. That was an investment that the district considered and eventually they decided it was worth a try.”

As schools weigh the economic costs against the benefits, De La Iglesia hopes that policymakers consider the impact later start times might have on teen health and its potential for closing socioeconomic gaps that impact education. The new study, he hopes, brings the hidden value of both aspects of this measure into focus.

“I think the results indicate that the investment was worth it,” he adds.