By Dr. Dawn Dore-Stites

We can all agree that a good education establishes a solid foundation for children and adolescents and leads to more informed citizens with higher incomes; however, proposing new ways to improve aspects of the educational experience is often the cause of conflict and debate among teaching professionals and parents.

Imagine, though, if a single potential improvement existed that

  • Increased academic performance;
  • Decreased tardiness and absence from school;
  • Decreased risk behaviors;
  • Decreased incidence of depression;
  • Decreased frequency of motor vehicle accidents; and
  • Was endorsed by multiple professional organizations including the Center for Disease Control (CDC), the American Academy of Pediatrics (AAP), and the American Psychological Association (APA).

It would be logical to assume that the debate around this idea would be minimal...right? As it turns out, this beneficial and substantially-supported improvement is real and possible, and all that it requires is shifting middle and high school start times later.

Why later start times?

The rationale behind shifting middle and specifically high school start times later lies in how adolescents sleep. Starting around puberty, most teens shift to a later bedtime and later rise time. This is the result of biological factors that push the circadian rhythm later relative to younger children. For many, this shift in sleep patterns doesn’t even end until their mid-20s—long after high school ends.

Approximately 43% of schools across the nation start before 8 am despite recommendations from professional organizations to not have start times prior to 8:30 am. The 8:30 am start time was selected to provide an opportunity for an adolescent to get closer to the 8-10 hours of sleep per night recommended. Despite the numerous benefits of a full night of sleep, fewer than 1 in 5 middle and high schools actually have a start time of 8:30 AM or later.

Some argue that pushing for a later start time will just lead to teens going to bed later; however, school districts that have shifted start times found that the duration of sleep per night for their students did increase. Considering that less than 30% of high schoolers get more than 8 hours of sleep per night and that every hour of sleep lost can be associated with negative effects on mood, academics, and health, shifting start times may be a relatively straightforward way to improve the health of our teens.

Arguments for later start times

Increased academic performance

Schools that have moved to later start times have tracked academic benchmarks including GPA, standardized test scores, and attendance. Results have not been consistent but individual studies have shown decreased rates of tardies and absences as well as increased test scores. Effects appear to be most robust for students who perform at the lower end of the curve, indicating that shifting start times may be an especially important intervention for disadvantaged or struggling students.

Improved mood

Outside of academic behavior, some school districts have also tracked mental health functioning. Given that conditions such as depression are common in teens and can lead to significant and negative consequences such as suicide and substance use, measuring the impact on factors outside of academic performance is critical. Two studies have shown that delays in start time lead to decreased self-report of depressed mood among students—in the absence of any other interventions. Delaying school start times may not only be a crucial academic intervention, but also a critical public health initiative.

Improved safety

One of the more researched aspects of shifting school start times has focused on motor vehicle accidents. One study looked at accident rates before and after a district went to a delayed start time. The findings were again positive: accident rates decreased by 16.5% over a 2-year period in the district moving to later start times—despite the accident rate increasing by 7.8% in the state as a whole. Results from other studies demonstrate similar findings. Considering that teens are novices at driving, optimizing their sleep before they get behind the wheel has public safety implications—not only for them but for others on the road.

Arguments against later start times

Again, any change in education brings debate—even one that promotes several benefits. For school districts that have moved through the shift to later times, logistical arguments against the shift often predominate conversations. Scheduling extracurricular activities, managing bus schedules, decreased hours available for after-school employment, and shifting elementary school start times earlier often enter arguments. School districts have managed this in a variety of ways and there have been creative solutions to many of the barriers.

The organization Start School Later has a variety of resources to help parents and school personnel navigate conversations around these changes. That said, while arguments against changing school start times abound, the vast majority of school districts that have made the change to later start times have not returned to earlier start times due to the multiple benefits observed.

What you can do now

Changing a school district’s start time can be an overwhelming mission. However, there are things that can help individual students now. For parents, modeling good sleep practices including establishing bedtimes and limiting electronics in the bedroom can emphasize this critical component of health. For teachers, understanding the time constraints students face when trying to balance homework demands and appropriate bedtimes can lead to more informed assignments. For both concerned parents and teachers, starting discussions among PTA groups or other organizations on the importance of sleep can be a good first step. Overall, it takes work in the home and at school to help teens sleep more and sleep better.

The bottom line

Shifting school start times results in changes that cause ripples across several areas. Overall, the positive outcomes described above outweigh the short-term disruptions that dramatic shifts in schedules initiate. In the meantime, helping teens, parents, and school personnel recognize the significant impact increased sleep duration has on health and well-being can be a dynamic first step.

About Dawn Dore-Stites, PhD

Dawn Dore-Stites works at the University of Michigan Pediatric Sleep Clinic where she works with children and adolescents struggling with sleep disorders. She specializes in Child Psychology and Sleep and is a mother of two beautiful children.


American Academy of Pediatrics. “School Start Times for Adolescents.” Pediatrics, vol. 134, no. 3, 2014, pp. 642–649., doi:10.1542/peds.2014-1697.