Arguments for and Against Later High School Start Times

Medical Groups Urge High School Classes Start after 8:30 a.m.

Researchers and medical associations have determined that a late start to the high school day may help teens who need more sleep.

Most high schools in the United States begin the school day early, often before the first rays of the sun peek over the horizon. The average start times range state by state from 7:40 a.m. (Louisiana) to 8:33 a.m.(Alaska). The reason for such early hours can be traced back to the suburban sprawl of the 1960s and 1970s that increased the distances between schools and homes. Students could no longer walk or ride bicycles to school.

Suburban school districts responded to these shifts by providing bus transportation. The pick-up/drop-off times for students were staggered so the same fleet of buses could be used for all grades. High school and middle school students were assigned the earlier start, while elementary students were picked up once the buses had completed one or two rounds.

The economic decisions for staggered transportation made years ago are now being countered by a growing body of medical research that simply states that schools should start later because teens need sleep.

The Research

For the past 30 years, there has been a growing body of research that has documented the biologically different sleep and wake patterns of teenagers compared to younger students or adults. The biggest difference between adolescent and other sleep patterns is in circadian rhythms, which the National Institute of Health defines as the "physical, mental, and behavioral changes that follow a daily cycle.” Researchers have found that these rhythms, which respond primarily to light and darkness, differ among different age groups.

In one of the early (1990) studies "Patterns of Sleep and Sleepiness in Adolescents", Mary A. Carskadon, a sleep researcher at the Warren Alpert Medical School of Brown University, explained:

“Puberty itself imposes a burden of increased daytime sleepiness with no change in nocturnal sleep…. Development of circadian rhythms may also play a role in the phase delay teenagers commonly experience. The primary conclusion is that many adolescents do not get enough sleep.”

Acting on the basis of that information, in 1997, seven high schools in the Minneapolis Public School District decided to delay the start time of seven comprehensive high schools to 8:40 a.m. and extend the dismissal time to 3:20 p.m.

The results of this shift were compiled by Kyla Wahlstrom in her 2002 report "Changing Times: Findings From the First Longitudinal Study of Later High School Start Times."

The initial results of the Minneapolis Public School District were promising:

  • The attendance rates for all students in grades 9, 10, and 11 improved in the years from 1995 to 2000.
  • The high school students continued to get an hour more sleep on school nights.
  • The increased sleep continued four years into the change.
  • Students got five more hours of sleep per week than did peers in schools that started earlier.

By February 2014, Wahlstrom also released the results of a separate three-year study. This review focused on the behaviors of 9,000 students attending eight public high schools in three states: Colorado, Minnesota, and Wyoming.

Those high schools that started at 8:30 a.m. or later showed:

  • 60% of students got at least eight hours of sleep per school night.
  • Those teens with fewer than eight hours of sleep reported significantly higher depression symptoms, greater use of caffeine, and a greater risk for substance use.
  • There was a positive improvement in grades earned in core subject areas of math, English, science, and social studies.
  • There was a statistically significant increase in the 1st-period grade point average in core subject areas.
  • There was a positive improvement in academic performance on state and national achievement tests.
  • There was a positive improvement in attendance rates and reduction in tardiness.
  • There was a significant 70% decrease in the number of car crashes (Wyoming) during the first year for teen drivers from 16 to 18 years of age.
  • The number of car crashes overall decreased by an average of 13%.

The last statistics on teen car crashes should be considered in broader context. A total of 2,820 teenagers ages 13-19 died in motor vehicle crashes in 2016, according to the Insurance Institute of Highways Safety.

In many of these crashes, sleep deprivation was a factor, causing reduced reaction times, slower eye movements, and a limit on the ability to make quick decisions.

All of these results reported by Wahlstrom, confirm the findings of Dr. Daniel Buysse who was interviewed in the 2017 New York Times article “The Science of Adolescent Sleep” by Dr. Perri Klass.

In his interview, Buysse noted that in his research on adolescent sleep, he found that an adolescent’s sleep drive takes longer to build up than it did in childhood, “They don’t reach that critical level of sleepiness till a later time at night.” That shift into a later sleep cycle creates a conflict between the biological need for sleep and the academic demands of the earlier school schedule.

Buysse explained that this is why the advocates for a delayed start believe an 8:30 a.m. (or later) start time improves students’ chances of success. They argue that teenagers cannot focus on difficult academic tasks and concepts when their brains are not fully awake. 

Problems in Delaying Start Times

Any move to delay the start of schools will require school administrators to confront well-established daily schedules. Any change will affect the schedules of transportation (bus), employment (student and parent), school sports, and extracurricular activities.

  • Transportation Concerns: Early start times were implemented in order for school districts to provide bus transportation using the same buses for elementary and high school students. A  later start time for high schools could require additional buses or earlier elementary school start times. 
  • Parental Supervision: In a delayed start, there may be parents of high school students who will no longer be able to drive students to school and get to work on time. This shift would mean high school students would have the responsibility of getting themselves ready for school. If elementary schools start earlier, however, the dismissal time will be earlier as well, and that may require more hours of after-school daycare. At the same time, parents of elementary students would be able to start work earlier and not worry about before school daycare.
  • Sports or Extracurricular Activities: For students who participate in sports or other extracurricular activities, a delayed start will mean later these activities will end several hours after school. The later hours could limit the available time for study, homework, and social activities. Coordination of sports schedules with other schools in area leagues or divisions would be difficult unless all other participating schools also delayed sports schedules. The available hours of daylight would limit outdoor practice for fall and spring sports unless costly lighting was provided. Community use of school facilities would be delayed as well. 
  • Employment: Many students work to save money for college or another career related goal. Some students have internships. Employers of teens would have to adjust the work schedules for students if school dismissal times were to change. Should elementary schools begin earlier, there would be a need to increase afterschool daycare opportunities. High school students, however, would not be available to work in a daycare for the first hour or two.

    Policy Statements

    For districts that are considering a delayed start, there are powerful statements of support from the American Medical Association (AMA), the American Academy of Pediatrics (AAP), and the Centers for Disease Control and Prevention (CDC). The voices of these agencies argue that these early start times may contribute to poor attendance and a lack of focus on academic tasks. Each group has made recommendations that schools should not begin until after 8:30 a.m.

    The AMA adopted a policy during its Annual Meeting in 2016 which gave their endorsement to encourage reasonable school start times that allow students to get sufficient sleep. According to AMA Board Member William E. Kobler, M.D. there is evidence that suggests appropriate sleep improves health, academic performance, behavior, and general well-being in adolescents. The statement reads:

    “We believe delaying school start times will help ensure middle and high school students get enough sleep, and that it will improve the overall mental and physical health of our nation's young people."

    Similarly, the American Academy of Pediatrics supports the efforts of school districts to set start times for students the opportunity to get 8.5–9.5 hours of sleep. They list the benefits that come with starting later with examples: "physical (reduced obesity risk) and mental (lower rates of depression) health, safety  (drowsy driving crashes), academic performance, and quality of life."

    The CDC reached the same conclusion and supports the AAP by stating, “A school system start time policy of 8:30 a.m. or later provides teenage students the opportunity to achieve the 8.5–9.5 hours of sleep recommended by AAP.”

    Additional Research

    Some studies have found a correlation between teen sleep and crime statistics. One such study, published (2017) in The Journal of Child Psychology and Psychiatry, stated that,

    “The longitudinal nature of this relationship, controlling for age 15 antisocial behavior, is consistent with the hypothesis that adolescent sleepiness predisposes to later antisociality.”

    In suggesting that sleep problems really might be the root of the problem, researcher Adrian Raine explained, “It may be that just educating these at-risk kids with simple sleep-hygiene education might actually make a bit of a dent in the future crime statistics.”

    Finally, there is promising data from a Youth Risk Behavior Survey. Relationships between hours of sleep and health-risk behaviors in U.S. adolescent students (McKnight-Eily et al., 2011) showed eight or more hours of sleep illustrated a kind of  “tipping point” in at-risk behaviors of teenagers. For teens who slept eight or more hours each night, the use of cigarette, alcohol, and marijuana declined by 8% to 14%. In addition, there was a  9% to 11% drop in depression and sexual activity. This report also concluded that school district must have a greater awareness of how sleep insufficiency impacts student academic performance and social behaviors.


    There is ongoing research providing information on the impact of delaying school starts for adolescents. As a result, legislatures in many states are considering later start times

    These efforts to gain the support of all stakeholders are being made in order to respond to the biological demands of adolescents. At the same time, the students may be agreeing with the lines about sleep from Shakespeare’s "Macbeth" that could be part of an assignment:

    “Sleep that knits up the raveled sleave of care,
    The death of each day’s life, sore labour's bath.
    Balm of hurt minds, great nature's second course,
    Chief nourisher in life's feast” (Macbeth 2.2:36-40)

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    Your Citation
    Bennett, Colette. "Arguments for and Against Later High School Start Times." ThoughtCo, Mar. 5, 2018, Bennett, Colette. (2018, March 5). Arguments for and Against Later High School Start Times. Retrieved from Bennett, Colette. "Arguments for and Against Later High School Start Times." ThoughtCo. (accessed March 21, 2018).