You Snooze, You Win

A case for delaying school start times for adolescents

Posted May 13, 2016

Gabrielle Lewine
Source: Gabrielle Lewine

This guest post was written by Gabrielle Lewine, a doctoral candidate in clinical psychology at the University of Southern California.

“Just 5 more minutes...” Every parent of an adolescent has heard this refrain. When you are running around looking for your left shoe and trying to prepare a nutritionally passable breakfast that can be eaten in less than a minute, a snoozing adolescent is just another weekday morning hassle. But what if our sleepy teens are onto something? This scurried routine, practiced 5 times per week but somehow never mastered, typically takes place before sunrise. Scientific research on sleep tells us that adolescent circadian rhythms are mismatched with the early start times of most high schools.

Circadian rhythms are our internal clock, driving our sleep cycles through the snooze-inducing hormone melatonin. When children hit puberty, changes in the timing of melatonin production lead to a night owl effect – adolescents tend to stay up later at night and sleep later in the morning compared to both children and adults. However, across the country, high schools typically have the earliest start time, followed by middle schools, followed by elementary schools. The average start time of middle and high schools is 8:03am. Therefore, changes in circadian rhythms that make it harder for adolescents to wake up early coincide with changes in school start time that require adolescents to wake up earlier than before. Makes sense, right?

Research shows that students can reap huge benefits from delayed start times. For example, with a start time of 7:30am, only one-third of high school students report sleeping 8 or more hours per night. In contrast, with a start time of 8:55am, this figure jumps to two-thirds. The proven consequences of sleep deprivation in teenagers are multitudinous: poorer academic performance, poorer cardiovascular health, more tardiness, increased likelihood of depression, substance use, and car accidents, just to name a few.

Alan Cleaver, Creative Commons license
Source: Alan Cleaver, Creative Commons license

The largest study of delayed school start time to date examined the impact of delaying start time by 30-80 minutes on 9000 students in Minnesota, Colorado, and Wyoming. The results were astounding. With the delayed start time, students earned better grades in math, science, social studies, and English, as well as improved performance on standardized tests. Tardiness decreased schoolwide while attendance improved. Perhaps even more striking – the number of automobile accidents involving teenagers in these districts was reduced by 70%.

Okay, so delaying school start times improves grades. But by how much? A study with freshman students at the US Air Force Academy found that the impact of a 50-minute start time delay on academic performance was equivalent to improving teacher quality by one standard deviation. Given the vast efforts devoted to training better teachers in this country, the fact that such a simple change could trigger an improvement in grades of this magnitude is staggering. Furthermore, although students at all academic levels benefit from a delayed start time, lower-achieving students experience a greater benefit from the delay than their higher-achieving peers. Therefore, delaying start time may provide an opportunity to even the playing field for students at all levels of academic performance.

These studies were not the only ones of their kind. A 30-minute delay in school start time at a private high school in Rhode Island found similar outcomes: increased sleep duration, improved class attendance, and less tardiness. In addition, this study found that a delayed start time led to improved motivation, reduced Health Center visits, and increased consumption of hot foods (e.g., eggs, sausages) at breakfast. The students were not the only ones impacted – a teacher at the school described the delayed start time as “the single most positive impact to [his] general quality of life at the school since [he] started 12 years ago.”    The mismatch between adolescent sleep patterns and school start time has garnered the attention of many policy makers. Individual school districts across the United States have started to see the light (of sunrise) and delayed their start times to map onto what sleep researchers advocate as best practice: a start time of 8:30am. Some schools have gone even further – in fact, the School for the Talented and Gifted, a Dallas high school that has been ranked #1 in the country for 5 consecutive years, has a start time of 9:15am. Coincidence? I think not.

So why would anyone oppose delaying school start time? As always, there are two sides to every story, and some school officials have concerns about making the switch. For example, schools have encountered resistance from coaches and parents of student athletes. Starting school later means ending school later – this means cutting into sports practice time or ending practice later in the evening, which could lead to additional financial burden (e.g., to install lighting for athletic fields). At the same time, students’ athletic performance might improve if a delayed start time got them closer to the 8.5-9.5 hours of sleep recommended for adolescents.

CollegeDegrees360, Creative Commons license
Source: CollegeDegrees360, Creative Commons license

Another costly concern is related to bus schedules. In most school districts, the start times of elementary, middle, and high schools are staggered so that only one fleet of buses is needed. If high school start times were delayed while elementary and middle school start times stayed constant, school districts would have to increase their fleet. Increasing the number of buses, plus staffing each bus with a bus driver and bus aide, plus providing insurance and benefits for these additional employees, can add up – the addition of one bus has an estimated cost of $60,000 per year. Alternatively, the start times of elementary and middle schools could either be pushed earlier or delayed in order to maintain the staggered start time, in which case no additional buses would be needed. However, the director of communications for the Michigan school district, Liz Margolis, stated that “A change to the elementary school start time…would disrupt the families’ schedules”. She called the possibility of a delayed start time “a cultural shift in how we provide service.”

            And indeed, she is right. This cultural shift would involve taking a look at the status quo and being honest about the fact that it is time for a change. Over 25% of high school students report falling asleep in class at least once per week. Adolescents are the group with the highest risk of automobile accidents. Less than one-third of high school students get the recommended amount of sleep. These figures cannot be ignored. To delay or not to delay? What is paramount when it comes to secondary education? Call me an idealist, but I think the top priority for educational practices should be to educate our children. Logistical issues notwithstanding, scientific evidence clearly tells us that delaying school start time improves the education, health, and well-being of adolescents. Will implementing a later start time come at some financial cost? Certainly. Will this policy change be “a logistical nightmare for administrators,” as U.S. News and World Report predicts? Perhaps. But is it worth it? Absolutely.


Bruzga, D. A., & Eastman, F. V., Jr,. (2014). Preliminary Report: High School Start Time (Phase I Findings) (Rep.).

Carrell, S. E., Maghakian, T., & West, J. E. (2011). A's from Zzzz's? The causal effect of school start time on the academic achievement of adolescents. American Economic Journal: Economic Policy, 3(3), 62-81.

Lewis, L. L. (2016, April 20). The U.S.'s best high school starts at 9:15a.m. Slate.

Pannoni, A. (2014, March 24). Later high school start times a challenge for districts. Retrieved from

Shapiro, T. M. (2015). The educational effects of school start times. IZA World of Labor, (181), 1-10.

Wahlstrom, K., Dretzke, B., Gordon, M., Peterson, K., Edwards, K., & Gdula, J. (2014). Examining the impact of later school start times on the health and academic performance of high school students: A multi-Site study. Center for Applied Research and Educational Improvement. St Paul, MN: University of Minnesota.

Wheaton, A. G., Ferro, G. A., & Croft, J. B. (2015, August 07). School start times for middle school and high school students — United States, 2011–12 School Year. Retrieved from