Delaying School Start Time Research Articles

Delayed school start time is associated with better sleep, mental health, and life satisfaction among residential high-school students: A prospective study.

This study examined the longer-term individual- and school-level changes in students seven months after a one-hour delay in school start time (SST). Two cohorts of Grade 11 students (N = 227; 60.8% female, age = 17.0 [0.85]) at a residential high school in Hong Kong completed a questionnaire assessing sleep duration, insomnia symptoms, depression, anxiety, stress, and subjective well-being in 2017 and 2018, respectively. One of the cohorts was reassessed seven months after the implementation of a delay in SST, from 7:30am to 8:30am (n = 83, 65.1% female). School-level data on breakfast consumption, attendance, tardiness, and health clinic visits were collected. Between-group and within-group prospective comparisons suggest that the delay in SST was associated with improved sleep duration, mental health, and life satisfaction. School-level data revealed increased breakfast consumption and decreased unexcused absences, tardiness, and clinic visits.

The Impacts of Delaying School Start Time on Sleep and Academic Performance in the Adolescent Population

Sleep has a significant impact on the physical and mental health of adolescents. However, most adolescents face sleep deprivation and a range of adverse consequences. The policy of delaying the start of school has gained the attention of many researchers in the last two decades in response to the problem of improving sleep quality and increasing the total number of hours of sleep among adolescents. This paper assesses the influences of delayed school start times on adolescent sleep and related outcomes, identifies the limitations and shortcomings of this policy implementation, and the available research data, provides a comprehensive analysis of the impacts of delayed school start times, and offers suggestions for the future direction and prospects of this policy implementation.

Challenged by extremely irregular school schedules, Uruguayan adolescents only set their waking time

Early school start times adversely influence adolescents' sleep duration. Late school start times and remote learning are associated with longer sleep durations. We leveraged a highly variable school schedule adopted after the first SARS-CoV-2 wave in Uruguay to study the influence of a hybrid mode of instruction (in-person/remote) with irregular school start times on adolescents' sleep. Objective sleep on school nights (120 observations) was determined using accelerometry recordings of 15 high-school students (3 males 15-17 years old). We used mixed-effects regressions to explore the influence of the mode of instruction (in-person/remote) and school start time on adolescents' sleep patterns(onset, end, and duration). An irregular individual regime of 2-6 school days per week, either in-person or remote, and with irregular start times (range: 07:30-12:00) wereobserved during the studied period. Remote learning delayed sleep end by 48 ± 9 min and increased sleep duration by 36 ± 12 min. In addition, 1 h delay in school start time delayed sleep end in 36 ± 4 min and increased sleep duration in 34 ± 5 min. A strong linear association of the mode of instruction and the school start time with participants' sleep was observed: Only waking time was associated with both school start time and mode of instruction, and sleep duration increased when students were taught remotely and when school started later. These results add evidence to the effectiveness of delaying school start time to improve adolescents' sleep. However, these efforts may not overcome the influence of a very late circadian orientation, as observed in Uruguayan adolescents.

Association of Delaying School Start Time With Sleep–Wake Behaviors Among Adolescents

PurposeFew adolescents spend enough time asleep on school nights. This problem could be addressed by delaying high school start times, but does this translate to reduced prevalence of sleep–wake problems like awakening too early or feeling sleepy during the day? MethodsThe START study (n = 2,414) followed a cohort of students from five Minnesota high schools to evaluate impacts of school start time delays. Participants were enrolled in ninth grade (Baseline) when all schools started early (7:30 or 7:45 a.m.). At Follow-Up 1 (10th grade) and Follow-Up 2 (11th grade), two schools had delayed their start times by 50 and 65 minutes while three comparison schools started at 7:30 a.m. Six sleep–wake behaviors were assessed at all three time points via survey. Generalized estimating equation models were used to investigate changes in sleep–wake problems between policy change and comparison schools. ResultsThe prevalence of sleep–wake problems at Baseline ranged from 11% for being late to class due to oversleeping to 48% for needing to be told to wake multiple times in the morning. Compared to students from comparison schools, students at policy change schools reported smaller increases in the prevalence of feeling sleepy daily and oversleeping and being late to class between 9th and 11th grade. After implementation of the delayed start, awakening too early was more common among students at policy change schools compared to the comparison schools. ConclusionsThis longitudinal study provides evidence that delaying high school start times reduces daytime sleepiness and school tardiness.

The Association Between School Start Time and Sleep Duration, Sustained Attention, and Academic Performance.

PurposeIn adolescence, physiological (circadian and homeostatic regulation of sleep) and social habits contribute to delayed sleep onset, while social obligations impose early sleep offset. The effects of delayed school start time on the subjective/objective measures of sleep–wake patterns and academic achievement have not been established.MethodsThis pre-, post-, and longitudinal non-randomized study included an early (8:00 am; ESC=30 students) and the late (9:00 am; LSC=21 students) start class. Multiple sleep data included a weekly sleep diary, Karolinska Sleepiness Scale, Pittsburgh Sleep Quality Index, and Epworth Sleepiness Scale. Sustained attention was measured using the Psychomotor Vigilance Task. Academic performance was evaluated by two different mathematical and scientific standard tests (entrance and final) and by school attendance indicators. Data were collected at monthly intervals from October 2018 to May 2019 and the beginning and end of the academic year (pre/post).ResultsAll students turned their lights off at similar times (LSC=11:21pm, ESC=11:11pm), but LSC students woke up later (7:23am) than ESC students (6:55am; F1,48=11.81, p=0.001) on school days. The groups did not differ in total sleep duration on non-school days. Longitudinal measures revealed a significant increase (8.9%, 34 min) in total sleep duration of LSC students across the academic year. ESC students maintained approximately the same sleep duration. Furthermore, changes in sleep duration had parallelled significant differences in sustained attention, with LSC students outperforming ESC students. Longitudinal changes of sleep and sustained attention were associated with a coherent pattern of changes in academic performance.ConclusionFindings indicate that a one-hour delay in school start time is associated with longer sleep, better diurnal sustained attention, attendance, and improved academic performance. Notably, sleep changes were limited to school days. A delay in school start time should be seriously considered to improve sleep and academic achievements of students.

The impact of COVID-19 related school shutdown on sleep in adolescents: a natural experiment

ObjectiveDuring the outbreak of the COVID-19 pandemic in 2020, high schools closed or transitioned to remote teaching. The aim of this study was to describe how the COVID-19 related school shutdown impacted the sleep behaviors of typically developing adolescents. MethodsA qualitative study was conducted between April 28 and June 3, 2020 with 45 adolescents using one-on-one semi-structured phone interviews. ResultsThe “natural experiment” caused by the shutdown of schools due to the COVID-19 pandemic led to a 2-h shift in the sleep of typically developing adolescents, longer sleep duration, improved sleep quality, and less daytime sleepiness compared to those experienced under the regular school-time schedule. DiscussionThese findings are consistent with previous studies showing that delaying high school start times could be an effective way to extend sleep duration, improve sleep quality, reduce daytime sleepiness and lower adolescents' stress during the school year. As many countries look for ways to reduce the number of interactions between students in schools so that physical distancing is feasible, following teens’ delayed sleep biology could offer an affordable solution. For example, staggering arrival times by delaying school start time for older adolescents compared with younger adolescents can reduce the total number of students attending school at the same time. This strategy offers a practical means to reduce school density and the number of interactions between students which are needed to reduce the potential transmission of COVID-19 in schools, while improving adolescents sleep health.

The effect of delaying school start time on adolescents’ time use and health: evidence from a policy change in South Korea

ABSTRACT This paper examines how delaying school start time to 9 o’clock affected the time use and health of secondary-school students in South Korea. To identify the causal effects of delaying school start time, we used a difference-in-differences methodology with two nationally representative datasets to take advantage of a unique natural experiment in South Korea. We found that the policy led students to sleep 16.1 min more on weekdays and 7.6 min less a day over the weekend, increasing sleep satisfaction among the affected students. Furthermore, the policy contributed to increased growth and improved mental health. However, the effects of the policy were not uniform across subgroups. In terms of time use, students from the highest socioeconomic group increased their sleep duration most. In contrast, students from the middle and lowest socioeconomic categories increased their use of electronic devices and decreased their study time compared to students from the highest socioeconomic group. We provide evidence that these behavioural differences by socioeconomic group could be related to the degree of parental monitoring and available economic resources.

Association of Delaying School Start Time With Sleep Duration, Timing, and Quality Among Adolescents

Sleep is a resource that has been associated with health and well-being; however, sleep insufficiency is common among adolescents. To examine how delaying school start time is associated with objectively assessed sleep duration, timing, and quality in a cohort of adolescents. This observational cohort study took advantage of district-initiated modifications in the starting times of 5 public high schools in the metropolitan area of Minneapolis and St Paul, Minnesota. A total of 455 students were followed up from grade 9 (May 3 to June 3, 2016) through grade 11 (March 15 to May 21, 2018). Data were analyzed from February 1 to July 24, 2019. All 5 participating schools started early (7:30 am or 7:45 am) at baseline (2016). At follow-up 1 (2017) and continuing through follow-up 2 (2018), 2 schools delayed their start times by 50 and 65 minutes, whereas 3 comparison schools started at 7:30 am throughout the observation period. Wrist actigraphy was used to derive indices of sleep duration, timing, and quality. With a difference-in-difference design, linear mixed-effects models were used to estimate differences in changes in sleep time between delayed-start and comparison schools. A total of 455 students were included in the analysis (among those identifying sex, 225 girls [49.5%] and 219 boys [48.1%]; mean [SD] age at baseline, 15.2 [0.3] years). Relative to the change observed in the comparison schools, students who attended delayed-start schools had an additional mean 41 (95% CI, 25-57) objectively measured minutes of night sleep at follow-up 1 and 43 (95% CI, 25-61) at follow-up 2. Delayed start times were not associated with falling asleep later on school nights at follow-ups, and students attending these schools had a mean difference-in-differences change in weekend night sleep of -24 (95% CI, -51 to 2) minutes from baseline to follow-up 1 and -34 (95% CI, -65 to -3) minutes from baseline to follow-up 2, relative to comparison school participants. Differences in differences for school night sleep onset, weekend sleep onset latency, sleep midpoints, sleep efficiency, and the sleep fragmentation index between the 2 conditions were minimal. This study found that delaying high school start times could extend adolescent school night sleep duration and lessen their need for catch-up sleep on weekends. These findings suggest that later start times could be a durable strategy for addressing population-wide adolescent sleep deficits.

Does delaying school start time change sleep hours and tiredness of Korean adolescents?

Does delaying school start time change sleep hours and tiredness of Korean adolescents?

Ten-Year Secular Trends in Sleep/Wake Patterns in Shanghai and Hong Kong School-Aged Children: A Tale of Two Cities.

To compare the secular trends of sleep/wake patterns in school-aged children in Hong Kong and Shanghai, two major metropolitan cities in China with two different policies that school start time was delayed in Shanghai, but advanced in Hong Kong in 10 years' time. Participants were from two waves of cross-sectional school-based surveys of children aged 6 to 11 years. In Shanghai, 4,339 and 13,795 children participated in the 2005 and 2014 surveys, respectively. In Hong Kong, 6,231 and 4,585 children participated in the 2003 and 2012 surveys, respectively. Parents reported their children's bedtime and wakeup time, and thus sleep duration, short sleep (≤ 9 hours) and weekend oversleep (difference in sleep duration between weekday and weekend > 2 hours) were determined. Hong Kong children had later bedtime and wakeup time and slept consistently less than their Shanghai counterparts at both survey time points. The shorter sleep duration was particularly marked during weekdays. Over the interval period, weekday sleep duration significantly decreased from 9.2 to 8.9 hours as wakeup time became earlier for Hong Kong children, but increased from 9.4 to 9.6 hours as wakeup time became later for children in Shanghai. Children from both cities slept longer on the weekends. Prevalence of weekend oversleep significantly increased in Hong Kong children, but no interval change was found in Shanghai children. The findings indicate subcultural differences in sleep/wake patterns in Shanghai and Hong Kong school-aged children. In particular, sleep duration had increased for Shanghai children, but decreased for Hong Kong children over 10 years. The benefits and barriers of delaying school start time for optimizing sleep health in school-aged children should be further explored.

A quasi-experimental study of the impact of school start time changes on adolescents’ mood, self-regulation, safety, and health

ObjectiveTo determine whether school start time changes impact adolescents’ mood, self-regulation, safety, and health. MethodsIn September 2015, two school start time changes were implemented in Fairfax County (VA) Public Schools: a 50-minute delay (to 8:10 am) for high schools and secondary schools and a 30-minute advance (to 7:30 am) for middle schools. We conducted cross-sectional surveys of students’ sleep, mood, self-regulation, health, and safety before (2017 students) and after (1180 students) these changes. ResultsAdjusted for confounders, a 50-minute delay was associated with a decreased prevalence of low mood (−4.7%; 95% confidence interval [CI]: −8.2%, −1.2%), drowsy driving, (−8.4%; 95% CI: −15.9%, −0.9%), and skipping breakfast (−4.2%; 95% CI: −8.1%, −0.2%) but no other significant changes. There were no significant changes associated with a 30-minute advance. ConclusionsA 50-minute delay in school start time in high schools and secondary schools was associated with a decreased prevalence of low mood, drowsy driving, and skipping breakfast. A 30-minute advance in start time in middle schools was not associated with any appreciable changes.

Effects of a 20 minutes delay in school start time on bed and wake up times, daytime tiredness, behavioral persistence, and positive attitude towards life in adolescents

ObjectivesPreliminary evidence suggests that delaying school start times is an effective tool for improving adolescent sleep duration. Our study assessed whether a policy driven 20-minute delay in school start times led to an increase in adolescents’ weekday bed and wake up times. MethodData collected via school satisfaction surveys concerned 663 students (45.2% females, Mean age: 14.91 years, SD = 0.58 years) in three lower-track secondary schools in Switzerland. Of all the students, 249 experienced a policy-driven 20-minutes school start time change (SSTc), from 7.40 am to 8.00 am between the eighth and ninth grade, while 414 students did not (Comparison Group/CG). Students filled out the survey twice, at the end of their eighth and ninth grades, respectively, and reported their weekday bed and wake up times, daytime tiredness, behavioural persistence, and positive attitude towards life. ResultsGeneralized estimating equations models of bed and wake up times showed that there was a significant delay in both the bed and wake up times of the students in the SSTc group. Multilevel analyses revealed that students in the SSTc group did not significantly differ from CG students in daytime tiredness, behavioural persistence, and positive attitude towards life. ConclusionsFindings suggest that not only wake up times but also bed times may shift later when school start times are delayed. The 20 minutes delay in school start times may have been too slight to have an impact on daytime tiredness, behavioral persistence and positive attitude towards life.

Effect of Delaying School Start Time on Sleep Quality, Emotions, and Performance in Korean Adolescents

Effect of Delaying School Start Time on Sleep Quality, Emotions, and Performance in Korean Adolescents

Later high school start times associated with longer actigraphic sleep duration in adolescents.

High school start times (SSTs) directly impact adolescents' sleep timing and duration. This study investigated the associations between SSTs and actigraphically-measured 24-hour sleep duration, sleep onset, sleep offset and sleep quality. This study included 383 adolescents (Mage = 15.5, SDage = 0.6 years) participating in the age 15 wave of the Fragile Families & Child Wellbeing Study, a national birth cohort study sampling from 20 large US cities. Multilevel models used daily observations (N = 1116 school days, Mdays = 2.9, SDdays = 1.4 per adolescent) of sleep and SSTs from concordant daily diary and actigraphy. A diverse range of SSTs were included in our analyses (MSST = 08:08, SDSST = 39 minutes, RangeSST = 06:00-11:05), and are presented in the following categories for ease of interpretation: before 07:30, 07:30-07:59, 08:00-08:29, and 08:30 or later. Adolescents starting school at 08:30 or later exhibited significantly longer actigraphically-assessed 24-hour sleep duration (by 21-34 minutes, p < .05) and later sleep offset (by 32-64 minutes, p < .001) when compared with the adolescents grouped by earlier SSTs. SSTs were also analyzed continuously for comparison with existing literature, and results indicated that every 1-hour delay in SST was significantly associated with 21 minutes longer 24-hour sleep duration (p < .001), 16 minutes later sleep onset (p < .01), and 39 minutes later sleep offset (p < .001). All models controlled for covariates including socioeconomic status. These findings support pediatric and public health expert recommendations for SSTs after 08:30. In our diverse national urban sample, adolescents with SSTs at 08:30 or later, compared with adolescents with earlier SSTs, had significantly longer actigraphy-measured sleep.

School Start Time and the Healthy Weight of Adolescents

PurposeStudies have found that an early school start time is detrimental to the sleep, health, and well-being of youth, but its association with body weight remains unclear. We examined this association in Canadian adolescents. MethodsWe collected information on start times from 362 schools that participated in the 2013/2014 Canadian Health Behaviour in School-aged Children Study (n = 29,635 students; ages 10–18). We estimated body mass indices (BMIs) and BMI z-scores, and identified overweight and obesity using international growth references. Multilevel regression models tested the associations between school start times and our outcomes, adjusted for grade, family affluence, school rurality, latitude, and province. ResultsThe average BMI was 21.2 (standard deviation 4.9) and BMI z-score was .48 (standard deviation 1.23). Every 10-minute delay in school start time corresponded with a .02 (95% confidence interval .00, .04) smaller BMI z-score. This association translated to BMIs in the 70th and 64th percentiles when comparing students from schools that started at 8:00 a.m. and 9:30 a.m., respectively. School start time was not significantly related to overweight or obesity. ConclusionsLater school start time was linked to lower BMI in Canadian adolescents. Delaying school start time may be an additional strategy to support the healthy weight of adolescents. Future intervention and impact studies are recommended to confirm these findings.

0808 A Prospective Study of Self-Reported Sleep After a Delay in School Start Times

0808 A Prospective Study of Self-Reported Sleep After a Delay in School Start Times

School start times and teenage driver motor vehicle crashes

IntroductionShifting school start times to 8:30 am or later has been found to improve academic performance and reduce behavior problems. Limited research suggests this may also reduce adolescent driver motor vehicle crashes. A change in the school start time from 7:30 am to 8:45 am for all public high schools in one North Carolina county presented the opportunity to address this question with greater methodologic rigor. MethodWe conducted ARIMA interrupted time-series analyses to examine motor vehicle crash rates of high school age drivers in the intervention county and 3 similar comparison counties with comparable urban-rural population distribution. To focus on crashes most likely to be affected, we limited analysis to crashes involving 16- & 17-year-old drivers occurring on days when school was in session. ResultsIn the intervention county, there was a 14% downward shift in the time-series following the 75 min delay in school start times (p = .076). There was no change approaching statistical significance in any of the other three counties. Further analysis indicated marked, statistically significant shifts in hourly crash rates in the intervention county, reflecting effects of the change in school start time on young driver exposure. Crashes from 7 to 7:59 am decreased sharply (−25%, p = .008), but increased similarly from 8 to 8:59 am (21%, p = .004). Crashes from 2 to 2:59 pm declined dramatically (−48%, p = .000), then increased to a lesser degree from 3 to 3:59 pm (32%, p = .024) and non-significantly from 4 to 4:59 (19%, p = .102). There was no meaningful change in early morning or nighttime crashes, when drowsiness-induced crashes might have been expected to be most common. DiscussionThe small decrease in crashes among high school age drivers following the shift in school start time is consistent with the findings of other studies of teen driver crashes and school start times. All these studies, including the present one, have limitations, but the similar findings suggest that crashes and school start times are indeed related, with earlier start times equating to more crashes. ConclusionLater high school start times (>8:30 am) appear to be associated with lower adolescent driver crash rates, but additional research is needed to confirm this and to identify the mechanism by which this occurs (reduced drowsiness or reduced exposure).

Sustained benefits of delaying school start time on adolescent sleep and well-being

Study ObjectivesTo investigate the short- and longer-term impact of a 45-min delay in school start time on sleep and well-being of adolescents.MethodsThe sample consisted of 375 students in grades 7–10 (mean age ± SD: 14.6 ± 1.15 years) from an all-girls’ secondary school in Singapore that delayed its start time from 07:30 to 08:15. Self-reports of sleep timing, sleepiness, and well-being (depressive symptoms and mood) were obtained at baseline prior to the delay, and at approximately 1 and 9 months after the delay. Total sleep time (TST) was evaluated via actigraphy.ResultsAfter 1 month, bedtimes on school nights were delayed by 9.0 min, while rise times were delayed by 31.6 min, resulting in an increase in time in bed (TIB) of 23.2 min. After 9 months, the increase in TIB was sustained, and TST increased by 10.0 min relative to baseline. Participants also reported lower levels of subjective sleepiness and improvement in well-being at both follow-ups. Notably, greater increase in sleep duration on school nights was associated with greater improvement in alertness and well-being.ConclusionsDelaying school start time can result in sustained benefits on sleep duration, daytime alertness, and mental well-being even within a culture where trading sleep for academic success is widespread.

SAVED BY THE MORNING BELL: SCHOOL START TIME AND TEEN CAR ACCIDENTS

Adolescents today suffer from chronic sleep deprivation due to a combination of biological changes to the circadian clock and early morning school bell times. Many school districts are now considering delaying high school start times to accommodate the sleep schedules of teens. This paper explores whether such policy changes can have an unexpected impact on teen car accident rates. This impact could function both through a direct effect on teen sleep deprivation and indirectly through changes to the driving environment, that is, shifting the time and conditions under which teens commute to school. By focusing on late‐night accidents and employing a difference‐in‐differences strategy using adult drivers as a control group, I find evidence of a persistent sleep deprivation mechanism. A 15‐minute delay in school start time causes a significant decrease in late‐night teen accidents of approximately 23%. However, I also find evidence of an opposing mechanism that is present during the morning commuting hours. A 15‐minute delay in high school start time leads to a 21% increase in morning teen car accidents. (JEL I29, J13, R41)

The impact of delaying school start time in a Singapore school

The impact of delaying school start time in a Singapore school