The Impact of School Start Times on Adolescent Health and Academic Performance

“The timing of education is also important. There is clear evidence for a phase shift during adolescence, with adolescents going to bed later and rising later than children. This phase shift is largely biological, with adolescents typically unable to fall asleep at earlier times. For the most part, school systems have not considered this adolescent phase shift, with many systems traditionally having earlier (rather than later) start dates for high school than for grade school students. By recognizing the shift in biological rhythms during adolescence and delaying school start times accordingly, classroom experience can be matched to the times when adolescents are most alert and attentive.”—Donna Coch, Ed.D., Associate Professor and Chair, Department of Education, Dartmouth College, Kurt Fischer, Ph.D., Charles Bigelow Professor of Education, Director, Mind, Brain, and Education Program, Harvard University, Geraldine Dawson, Ph.D., Professor of Psychiatry and Behavioral Sciences, Pediatrics, Psychology and Neuroscience, Duke University Medical Center, Director of the Duke Center for Autism and Brain Development, Duke University. (Coch, Fischer, & Dawson, Human Behavior, Learning, and the Developing Brain: Typical Development (Informa Healthcare 2010) pp. 382-383.)

“There is a need for educators to be more aware of the impact of school start times and academic scheduling, and to consider sleep problems as potential factors in students who fail to achieve or who exhibit behavioural problems. While it may be administratively convenient to begin high school classes early, there is strong evidence in our data, supported by the literature, suggesting that later start times would be more appropriate for teens.” ⁽⁶³⁾

“We believe that high schools should take a close look at having later start times to align with circadian rhythms in teens and to allow for longer sleep times. Too many teens in this country obtain insufficient sleep. A burgeoning literature suggests that this may lead to problematic consequences including mood disorders, academic difficulties and behavioral issues.” ⁽³¹⁵⁾

“Where possible, efforts should be made to encourage lighter homework loads and later school start times, so that adolescents can go to bed and wake up at times that are more suited to their bodily rhythms.” ⁽²³⁾

“Students at later starting middle and high schools obtain more sleep due to later wake times and, in turn, function more effectively in school.” ⁽³⁰⁾ 

“The onset of puberty has been shown to be associated with a phase delay with later sleep onset and wake times. Lifestyle and social factors often mean a chronic sleep debt accumulates during the week, which the teenager attempts to address by sleeping in on weekends, which is ineffective and further contributes to the circadian disruption. Interestingly, the delay of school start time by half an hour from 8:00 to 8:30 A.M. results in a significant increase in sleep duration, with concomitant improvements in alertness, motivation, and mood in adolescents [¶] For adolescents, we suggest that school start times be delayed to align with the physiological circadian propensity of this age group.” ^(54.7)

“[S]chools need to incorporate into their pedagogical proposal measures that would reduce the impact of phase delay on the student’s performance. [¶] The first step would be to reconsider the school’s temporal organization, in particular its class schedules, and systematize the results of possible interventions that aim to reduce the student’s daily sleepiness and thereby improve performance. [¶] The changes we propose are apparently simple modifications, such as delaying the beginning of morning classes.” ⁽⁵⁷⁵⁾ 

“For policy makers, teachers and parents, these results provide a clear mandate. The effects of sleep deprivation on grades, car accident risk, and mood are indisputable. A number of school districts have moved middle and high school start times later with the goal of decreasing teenage sleep deprivation. We support this approach, as results indicate that later school start times lead to decreased truancy and drop-out rates.” ⁽¹⁰³⁾

“These analyses suggest that earlier high school-start times contributed to an increase in crash rates amongst teenagers in the United States. They are additional data suggesting that high school start times should be delayed to increase the amount of sleep that teenagers get during the school week and, hence, reduce the amount of sleep deprivation they incur.” ⁽³⁵²⁾

“School administrators would serve students and teachers better by moving the opening bell later. The weight of the evidence from decades of studies suggests that creating conditions to encourage student sleep would improve the students’ mood, energy, alertness, and academic performance. [¶] Schools are not solely responsible for the perfect storm of teen sleep, but they can make a huge difference by moving to a later start time. The result would be happier, healthier, more attentive, and better performing students in high school.” ⁽⁶¹⁰⁾

“In summary, although the decision to implement a later start time for middle and high school students is seldom without controversy, this study adds to a growing body of evidence suggesting compelling health benefits with even a very modest delay in school start time to align more closely with adolescents’ circadian rhythms. Furthermore, our results suggested that high school students in earlier grades and those with lower baseline sleep amounts were more likely to benefit from the delay in school start time. The findings indicate the importance of systemic countermeasures to mitigate against chronic sleep loss in adolescents.” ⁽¹⁰⁷⁾

“Any factors that demand early rise times are likely to have a negative impact on sleep duration, particularly in light of the strong biological tendency of adolescents to delay sleep. This study provides further support that U.S. adolescents would benefit from later school start times. … Early school start times as well as early morning sport training or study may have a negative effect on sleep and flow-on effects to daytime alertness and functioning. [P]arental help in maintaining a limit on late night activities may similarly have a protective role.” ⁽³¹⁴⁾

“Recent research has focused on the effects of daytime sleepiness in the student population. Poor sleep quality has been linked to increased tension, irritability, depression, more frequent use of alcohol and illicit drugs, accidents, and lowered academic performance. Sleep problems are common and unrecognized in the student group. The influence of sleep on learning and behavior has recently captured the attention of school districts across the United States and school administrators increasingly need to weigh the factual information about the biology of student sleep patterns against the competing demands of teachers’ work preferences and athletic and after-school schedules. [¶] [T]here is increasing data that early school start times result in increased daytime sleepiness, and altering the times to a later time period has positive effects on academic performance and sleepiness.” (Bijwadia & Dexter, The Student with Sleep Complaints, publish. in, Sleep: A Comprehensive Handbook (Lee-Chiong, edit., Wiley-Liss 2006) pp. 959, 960.)

“[C]hildren and adolescents with restricted sleep are at greater risk for increased oppositionality and irritability, as well as reduced attention, executive functioning, processing speed, behavioral/emotional regulation, motivation and academic achievement. … Certainly this causal link between sleep loss and impaired functioning in children and adolescents provides the impetus for consideration of delaying school start times, particularly for adolescents, who are experiencing a natural delay in circadian rhythm.” ⁽⁶¹¹⁾

“The single most profound difference we could make [i]n education … would be to let teens sleep on nature’s schedule (midnight to 9 a.m. or later).” ⁽⁶¹²⁾

“Consider altering early high school start times to allow for the sleep patterns of teens.” ⁽⁶¹³⁾ 

“While implementation may be complex, particularly when a change would bring a school’s schedule out of sync with neighboring systems, delaying school start times so that adolescents begin their instructional day later provides numerous benefits to the students and their broader community alike.” ^(54.3)

Start Time Recommendations, etc.

“Physicians, especially those who treat adolescents, have campaigned since 1994 to allow teenagers to start school later. It would be hard to imagine that their argument has weakened given the evidence from this study that delayed school start times of later than 8:30 AM suggest improved attendance and graduation rates. [¶] The overall findings from this study are consistent with, and extend the evidence in the literature. Improved attendance rates increase the likelihood of graduation completion. Every student should have an equal opportunity to graduate from school. If a delayed start time of later than 8:30 AM promotes improved student access to attending, learning, and graduating, then all of society benefits because increased graduation completion impacts quality of life.” ^(48.7)

“We … urge school districts to put adolescent students’ health as top priority and implement school start times consistent with their developmental needs. [¶] Whereas substantial evidence illustrating adverse consequences of inadequate sleep on psychological and physical health, and recommendations exist to adapt daytime school schedules to match sleep needs have been released, actual implementation of these recommendations have been limited. [¶] This is a call to action for the implementation of AAP/CDC recommendations across the state and nation.” ⁽⁵⁶⁾

“The often serious impact of this chronic under-sleeping is now evident in both high school and middle school students. [¶] For all students one of the most salient—and correctable—social factors contributing to student sleep deprivation, is school start times. [¶] In brief, there are two features of the circadian rhythm especially important to understand regarding sleep in teenagers: (1) the drowsy signal that cues bedtime is dependent on the dampening of circadian-dependent alertness; and (2) the physiology of puberty causes a shift in the circadian rhythm which delays the timing of this biological bedtime by about an hour. These two biological factors underlie the main difficulties faced by adolescents attending school before 9:00 a.m.: the general problem that one cannot easily fall asleep before their biological bedtime, and the additional problem that puberty creates a tendency for even later bedtimes. [¶] Though research has not yet identified an ideal school schedule, the wealth of evidence reviewed in this chapter and elsewhere strongly suggests that students have a better opportunity to be rested and ready to learn by delaying school start time to 8:30 a.m. or later.” ⁽²⁾

“Another short-term solution that can be implemented is to change the time we give standardized tests to 10:00 a.m. Almost all standardized tests in high schools begin at 8 am. Because this is when adolescents show their poorest performance levels, a change is clearly needed and would be relatively easy to negotiate.” ^(6, but see, n. 261 [study of 9th and 10th graders found “larks” outperformed “owls” on exams administered from 10 a.m. to noon].)

“[G]iven the analyses summarized here, there are clear benefits for students whose high schools start at 8:30 AM or later. This would include, for teens who reported they got at least 8 hours of sleep per night, that they were more likely to say they have good overall health and were less likely to report being depressed or using caffeine and other substances (e.g., alcohol, tobacco, other drugs). Other positive findings include a significant reduction in local car crashes, less absenteeism, less tardiness, as well as higher test scores on national achievement tests. … [¶] … [T]here are empirically-based positive outcomes for adolescents whenever the start time of their high school is moved to a later time—with the starting time of 8:30 AM or later clearly showing the most positive results.” ⁽³⁰⁹⁾

“During the school year, many teenagers find themselves nodding off during their early morning classes as high school bells ring around 7:30 a.m. While parents and teachers may attribute falling asleep during class to staying up too late checking Facebook statuses and texting with friends, medical evidence suggests that an early school start time before 8:30 a.m. is a greater culprit because classes are occurring when students’ brains and bodies are still in biological sleep mode.” ⁽³⁴¹⁾

“There are at least three policy changes that will assist in the prioritization of sleep: 1) healthcare policy requiring the inclusion of sleep questions on health service intake forms and health provider prompts, in much the same way that smoking or exercise are routinely discussed; 2) education policy mandating school start times no earlier than 9 a.m. for adolescents; and 3) medical education policy limiting the hours of medical interns’ and residents’ shifts.” ⁽⁶²⁹⁾

“The study strongly recommends that middle schools should consider delaying the school starting time by at least one hour. Such a change could enhance students’ cognitive performance by improving their attention level, increasing rate of performance, as well as reducing their mistakes and impulsivity.” ^(13, italics added [study shifted school schedules from 7:30 a.m. to 8:30 a.m.].)

“Schools with start times before 8:30 a.m. place students at a disadvantage in terms of arousal and alertness, not only for early morning classes but also throughout the day because adolescents’ biological rhythms are out of sync with typical school routines.” ⁽¹¹⁾

“Right now, high schools usually start earlier in the morning than elementary schools. But if school start times were based on sleep cycles, elementary schools should start at 7:30 and high schools at 8:30 or 8:45—right now it’s the reverse. School systems should be thinking about changing their start times. It would not be easy—they would have to change the busing system—but it would increase their student’s sleep time and likely improve their school performance.” ⁽¹⁴⁾

“Although providing a home environment to promote healthy sleep is the first step to eliminating sleep deprivation in adolescents, increased public awareness of the impact of sleep on learning and behavior is important. For this to occur legislation to ensure that high school start times not begin before 9:00 a.m. may help in reducing sleep deprivation leading to improved academic performance and behavior[.]” ⁽¹⁵⁾

“Overall, many adolescents confront a major challenge if schools begin earlier than 8:30 a.m.; many schools start too early in the morning for adolescents to get adequate sleep, whether in the United States or in other countries such as Canada, Israel, Brazil, or Italy. [¶] [S]chool administrators are being urged to acknowledge the evidence and to adjust school schedules accordingly (e.g., delay high school start times).” ^(12, citations omitted.)

“High school should start at 8:45 a.m., or better at 9 o’clock.” ⁽⁶³⁰⁾ 

“A long-term solution to chronic sleep deprivation in adolescents that others conducting research on adolescent sleep behaviors support may mean that high school start times should be no earlier than 8:30 A.M. The change in high school start times will need to occur at the state level so that school sports and social events can be coordinated among schools.” ⁽¹⁰⁰⁾

“Delaying middle and high school start time to 8:30 h or later can be an effective method to: 1. improve important sleep outcomes in adolescence, including weeknight total sleep time and reduce daytime sleepiness; 2. improve health and academic outcomes, such as depression, caffeine use, tardiness to class and staying awake in class; and 3. circumvent changes in weeknight bedtime or reduced participation in extracurricular activities.” ^(43.5)

“Probably, 9 o’clock would be the ideal start time for high schools.” ⁽⁶³⁴⁾

“In 1913, Terman and Hocking (1913) reported that sleep in adolescents in the western U.S. was longer than that previously reported in studies of English (n=6180) (Ravenhill 1910) or German (Bernhard 1908) children and adolescents. One of the factors that they felt explained this difference was that school start times were an hour later (9:00 AM) in the U.S. than those in Germany and England (7:00–8:00 AM). They go so far as to state, ‘The American practice of beginning at 9 o’clock is far wiser, and should never be changed unless for very special reasons.’ ” ^(305, quoting Terman & Hocking, The sleep of school children; its distribution according to age, and its relation to physical and mental efficiency (1913) J. Educational Psychology, p. 271.)

“[I]t may be strongly argued that both the urgency and the magnitude of the problem of sleep loss in adolescents and the availability of an intervention that has the potential to have broad and immediate effects are highly compelling. [¶] The American Academy of Pediatrics recognizes insufficient sleep in adolescents as a public health issue, endorses the scientific rationale for later school start times, and acknowledges the potential benefits to students with regard to physical and mental health, safety, and academic achievement. The American Academy of Pediatrics lends its strong support to school districts contemplating delaying school start times as a means of optimizing sleep and alertness in the learning environment and encourages all school administrators and other stakeholders in communities around the country to review the scientific evidence regarding school start times, to initiate discussions on this issue, and to systematically evaluate the community-wide impact of these changes (e.g., on academic performance, school budget, traffic patterns, teacher retention). [¶] Pediatricians and other pediatric health care providers (e.g., school physicians, school nurses) should provide scientific information, evidence based rationales, guidance, and support to educate school administrators, parent-teacher associations, and school boards about the benefits of instituting a delay in start times as a potentially highly cost-effective countermeasure to adolescent sleep deprivation and sleepiness. In most districts, middle and high schools should aim for a starting time of no earlier than 8:30 AM. However, individual school districts also need to take average commuting times and other exigencies into account in setting a start time that allows for adequate sleep opportunity for students.” ⁽⁵⁴⁾

“Synchronizing education start times to adolescent biology is the obvious way to address the problem of chronic sleep deprivation currently experienced by adolescents on school days. Astronomical time data and changes in sleep patterns from international studies show at the age of 10 biological wake time is about 06:30, so synchronized school starting times would be 08:30-09:00. At the age of 16 biological wake time is about 08:00, and synchronized school start times 10:00–10:30, and at 18 biological wake time is about 09:00, and synchronized education start times 11:00–11:30. [¶] Unfortunately almost all previous studies of later school start times used times before 09:00, an approach that significantly underestimated the scale of change needed.” ^(65, original emphasis.)

Appendix C, infra, Start Time Recommendations, etc., includes the text above and additional advisements from scientists (and economists), with full citations, author credentials, and links to many author profiles in html, docx, and pdf.