How Would Later School Start Times Affect Sleep?

Does your child struggle to wake up to get ready for school? Are they still sleepy in their classes, unable to concentrate, or even falling asleep during class? While frustrating, this is not an uncommon experience for adolescents in the United States.

The number of hours children need to sleep depends on their age. According to the National Sleep Foundation, children ages 6–13 need between 9 and 11 hours of sleep at night. Teenagers (ages 14–17) need 8–10 hours each night. However, studies have demonstrated that most American adolescents are not getting enough sleep. Nearly 60% of middle schoolers do not get enough sleep on school nights. For high schoolers, that number is over 70%.

Late bedtimes and early school start times are a contributing factor to a lack of adolescent sleep. A lack of sleep impacts overall student health, wellbeing, and academic success, and it can even have long-term health consequences.

What Are Common School Start Times?

In the United States, the average high school start time is 8:00 a.m. This time varies, though, depending on the state. Except for eight outlying states, each state’s average start time is between 7:45 a.m. and 8:15 a.m.

Other start time factors include the location of the school district and the school type. For example, 54% of high schools in the suburbs start before 8:00 a.m. By contrast, over half of charter high schools start after 8:00 a.m., and high schools with fewer than 200 students begin around 8:15 a.m on average. (This study did not include data on private schools.)

Data on average middle school start times is less recent and does not include public charter or private schools. When assessed by the CDC for the 2011–2012 school year, the average start time at middle schools in the United States was at 8:04 a.m.  This is slightly later than high schools. The middle school start times varied widely, too, depending on the state. This study also noted the start time for combined middle and high schools; the average was 8:08 a.m.

Best School Start Times

Both the American Academy of Sleep Medicine and the American Academy of Pediatrics recommend that both middle and high schools begin no earlier than 8:30 a.m. Both organizations want to ensure students get adequate sleep so that they are alert and prepared to learn at school.

Biology plays a large factor in the sleep cycles of children and adolescents. Around the beginning of puberty, most adolescents experience later sleep onset and wake times, also called “phase delay”. This phase delay can shift the body’s internal clock back by up to two hours. As a result, the average teenager cannot fall asleep until 11:00 p.m. and would do best waking up at 8:00 a.m. or even later.

A later school start time helps accommodate this biological need. Overall care for sleep hygiene, such as having a good night’s sleep and following back-to-school sleep tips, can also help adolescents regulate their sleep.

Other factors that affect student sleep are cultural expectations. American middle and high school students often take on various extracurricular activities — such as sports, clubs, and jobs — which often extend into the evening hours. High school students also have more homework, late-night technology use, and fewer parent-set bedtimes, all of which may cause students to stay up later than is appropriate for getting adequate sleep.

How Do School Start Times Affect School Performance?

Countless studies have shown that early school start times are associated with students getting less sleep, which negatively affects student academic performance. Students with less sleep have difficulty paying attention in class and are likely to have lower grades. They may also experience irritability and fatigue.

Other concerns with early school start times and the resulting insufficient sleep include:

• Increased likelihood for participating in risk-taking behaviors, such as bullying and fighting.

• Greater chance of unhealthy behaviors including alcohol and drug use and tobacco smoking.

• Higher risk of athletic injury.

• An increase of depressive symptoms and suicidal ideation.

• Increased risk of motor vehicle accidents.

A lack of sleep also has long-term physical and mental health consequences. Poor quantity and quality of sleep can lead to health concerns such as diabetes, cardiovascular disease, and obesity.

Why Are Later School Start Times Better?

Later school start times support the biological needs of adolescents; they increase the amount of sleep adolescents get. Other benefits of later start times include:

• Improved attendance at school.
• Decreased tardiness.
• Better student grades.
• Fewer occurrences of falling asleep in class.
• Reduced irritability and depressive symptoms.
• Fewer disciplinary issues.
• A decline of motor vehicle crashes. One study showed a 16.5% decrease in the teenage crash rate after the school start time was pushed back one hour.

Disadvantages of Later School Start Times

While there are numerous benefits of later school start times, there are a few possible negative outcomes:

• Scheduling conflicts. These may arise for athletic and academic competitions against schools with earlier start times and therefore an earlier dismissal.
• Transportation challenges. Later start times will likely mean more busses on the road later in the day; this could create more traffic and increase travel delays.
• Childcare. Some families rely on older students to care for younger siblings after school; this may be more difficult if high schools dismiss later than elementary or middle schools.

However, these problems can likely be solved with flexibility and thoughtful planning.

If you are concerned about a too-early start time for your child’s school, consider contacting your school board or other educational leaders to discuss delaying school start time.

Written by Logan Foley, Sleep Foundation.