Later school start times really do improve sleep time
April 10, 2018
Science Daily/Oxford University Press USA
A new study indicates that delaying school start times results in students getting more sleep, and feeling better, even within societies where trading sleep for academic success is common.
The study aimed to investigate the short and longer-term impact of a 45-min delay in school start time on sleep and well-being of adolescents.
Singapore leads the world in the Programme for International Student Assessment rankings, which measures international scholastic performance in 15-year-olds. East Asian students live in a culture where the importance of academic success is deeply ingrained. This drive for academic achievement leads to high attainment in international academic assessments but has contributed to the curtailment of nocturnal sleep on school nights to well below the recommended eight to ten hours of sleep, putting students at risk of cognitive and psychological problems.
In Singapore, school typically starts around 7:30 AM, which is one hour earlier than the 8:30 AM or later start time recommended by the American Academy of Pediatrics, the American Medical Association, and the American Academy of Sleep Medicine. Sleep deprivation among Singaporean adolescents is rampant, and the average time in bed on school nights is 6 and a half hours.
In July 2016, an all-girls' secondary school in Singapore delayed its start time from 7:30 to 8:15 in the morning by restructuring its schedule in a way that did not delay school end time. Researchers investigated the impact of starting school later on students' sleep and well-being one month and nine months after the institution of the start time delay.
The sample consisted of 375 students in grades 7-10 from an all-girls' secondary school in Singapore that delayed its start time from 7:30 to 08:15 in the morning. Researchers assessed self-reports of sleep timing, sleepiness, and well-being (depressive symptoms and mood) before the school made the schedule change, and evaluated the measures again at approximately one and nine months after the delay. Total sleep time was also measured.
Later school start times have been shown to benefit sleep and well-being in Western cultures, but its usefulness in East Asian countries where students are driven to trade sleep for academic success is less clear. Most studies on later school start times have been conducted in Western countries. These studies have consistently found increased sleep duration on school nights with later start times. However, the sustainability of sleep habit improvement is not as well characterized.
Researchers wondered if students would continue to get more sleep if schools delayed their start times; the gains may not be sustained if students gradually delay their bedtime. For example, one study found that the sleep gained two months after a 45-minute delay in start time was no longer observed after another seven months, due to a delay in the sleep period. Delaying bedtimes, partly as a result of mounting academic workload, is a pressing reality in most East Asian households. Compounding this erosion of sleep time in East Asian societies is the resistance to changing the already packed school schedules. For example, recently, a secondary school in Hong Kong agreed to delay its start time, but only by 15 minutes. Nevertheless, a four-minute increase in time-in-bed on weekdays was found, together with gains in mental health, prosocial behavior and better attentiveness in class and peer relationships.
The results of this new study indicate that after one month, bedtimes on school nights were delayed by nine minutes while the times students got up were delayed by about 32 minutes, resulting in an increase in time in bed of 23 minutes.
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.
Critically, with a later school start time the percentage of participants whose self-reported sleeping time on weekdays was at least 8 hours -- the amount generally considered appropriate for adolescents -- increased, from 6.9% to 16%. Total sleep time increased by about 10 minutes at the nine-month follow-up.
"Starting school later in East Asia is feasible and can have sustained benefits," said the paper's lead researcher, Michael Chee. "Our work extends the empirical evidence collected by colleagues in the West and argues strongly for disruption in practice and attitudes surrounding sleep and wellbeing in societies where these are believed to hinder rather than enhance societal advancement."
https://www.sciencedaily.com/releases/2018/04/180410084223.htm
Teens get more sleep when school starts later
December 1, 2017
Science Daily/Penn State
A later school start time could mean teens are more likely to get adequate amounts of sleep, according to researchers.
In a national study of urban teenagers, researchers found that high school start times after 8:30 a.m. increased the likelihood that teens obtained the minimum recommended amount of sleep, benefiting their overall health and well being.
"Teens starting school at 8:30 a.m. or later were the only group with an average time in bed permitting eight hours of sleep, the minimum recommended by expert consensus," said lead author Orfeu Buxton, associate professor of biobehavioral health at Penn State. "Later school start times were associated with later wake times in our large, diverse sample."
Buxton and colleagues report their findings Dec. 1 in Sleep Health, the Journal of the National Sleep Foundation, which devoted an entire special issue to the topic.
Teens with the earliest high school start times -- 7:00-7:29 a.m. -- obtained 46 minutes less time in bed on average compared with teens with high school start times at 8:30 a.m. or later.
School start times after 8:30 a.m. were associated with increased time in bed, extending morning sleep by 27-57 minutes compared to those teens with earlier school start times.
A common argument against later school start times is an assumption that teens will just stay up later.
"The presumption is if you let kids start school later they will simply go to sleep later and still not get enough sleep," Buxton said. "But that's a hypothetical scenario. There wasn't data to back that up."
While researchers did find that teens with the earliest school start times were going to bed earlier than those with 8:30 a.m. or later, the teens with earlier start times still did not get the recommended amount of sleep. Only those teens with schools that had a start time of 8:30 a.m. or later actually got the recommended amount of sleep, Buxton said.
One theory is that, despite going to bed earlier than their peers, teens with the earliest school start times didn't get enough sleep possibly due to anticipation of an early wake time the following morning, according to Buxton.
In addition, the investigators considered other research that looked at teens' "sleep debt," where teens make up for lost sleep on non-school days, leading them to wake up consistently and significantly later than those on school days.
Both anticipation and sleep debt can misalign teens' circadian clocks from expected early wake timing on school days, interfering with having consistent sleep.
Four hundred and thirteen teenagers completed an online daily diary each evening, beginning after 7 p.m., during seven consecutive days, including school days and non-school days during both the academic year and the summer, which was defined as September through May and June through August, respectively.
From each diary entry, researchers looked at the participants' reports of the previous night's bedtime, the time the teen woke up in the morning, whether or not the teen went to school, and the school start times.
Data collection included daily diary data from a subsample of the parent study, the Fragile Families and Child Wellbeing Study, which follows a longitudinal birth cohort of children born between 1998 and 2000 in 20 United States cities.
https://www.sciencedaily.com/releases/2017/12/171201091030.htm