Teens get more sleep, show improved grades and attendance with later school start time, researchers find
When Seattle Public Schools announced that it would reorganize school start times across the district for the fall of 2016, the massive undertaking took more than a year to deploy. Elementary schools started earlier, while most middle and all of the district’s 18 high schools shifted their opening bell almost an hour later — from 7:50 a.m. to 8:45 a.m. Parents had mixed reactions. Extracurricular activity schedules changed. School buses were redeployed.
In a paper published Dec. 12 in the journal Science Advances, researchers at the University of Washington and the Salk Institute for Biological Studies announced that teens at two Seattle high schools got more sleep on school nights after start times were pushed later — a median increase of 34 minutes of sleep each night. This boosted the total amount of sleep on school nights for students from a median of six hours and 50 minutes, under the earlier start time, to seven hours and 24 minutes under the later start time.
“This study shows a significant improvement in the sleep duration of students — all by delaying school start times so that they’re more in line with the natural wake-up times of adolescents,” said senior and corresponding author Horacio de la Iglesia, a UW professor of biology.
The study collected light and activity data from subjects using wrist activity monitors — rather than relying solely on self-reported sleep patterns from subjects, as is often done in sleep studies — to show that a later school start time benefits adolescents by letting them sleep longer each night. The study also revealed that, after the change in school start time, students did not stay up significantly later: They simply slept in longer, a behavior that scientists say is consistent with the natural biological rhythms of adolescents.
“Research to date has shown that the circadian rhythms of adolescents are simply fundamentally different from those of adults and children,” said lead author Gideon Dunster, a UW doctoral student in biology.
In humans, the churnings of our circadian rhythms help our minds and bodies maintain an internal “clock” that tells us when it is time to eat, sleep, rest and work on a world that spins once on its axis approximately every 24 hours. Our genes and external cues from the environment, such as sunlight, combine to create and maintain this steady hum of activity. But the onset of puberty lengthens the circadian cycle in adolescents and also decreases the rhythm’s sensitivity to light in the morning. These changes cause teens to fall asleep later each night and wake up later each morning relative to most children and adults.
Scientists generally recommend that teenagers get eight to 10 hours of sleep each night. But early-morning social obligations — such as school start times — force adolescents to either shift their entire sleep schedule earlier on school nights or truncate it. Certain light-emitting devices — such as smartphones, computers and even lamps with blue-light LED bulbs — can interfere with circadian rhythms in teens and adults alike, delaying the onset of sleep, de la Iglesia said. According to a survey of youth released in 2017 by the U.S. Centers for Disease Control and Prevention, only one-quarter of high school age adolescents reported sleeping the minimum recommended eight hours each night.
“All of the studies of adolescent sleep patterns in the United States are showing that the time at which teens generally fall asleep is biologically determined — but the time at which they wake up is socially determined,” said Dunster. “This has severe consequences for health and well-being, because disrupted circadian rhythms can adversely affect digestion, heart rate, body temperature, immune system function, attention span and mental health.”
The UW study compared the sleep behaviors of two separate groups of sophomores, all enrolled in biology classes at Roosevelt and Franklin high schools. One group of 92 students, drawn from both schools, wore wrist activity monitors all day for two-week periods in the spring of 2016, when school still started at 7:50 a.m. The wrist monitors collected information about light and activity levels every 15 seconds, but no physiological data about the students. In 2017, about seven months after school start times had shifted later, the researchers had a second group of 88 students — again drawn from both schools — wear the wrist activity monitors. Researchers used both the light and motion data in the wrist monitors to determine when the students were awake and asleep. Two teachers at Roosevelt and one at Franklin worked with the UW researchers to carry out the study, which was incorporated into the curriculum of the biology classes. Students in both groups also self-reported their sleep data.
Frequently Added Questions
There are a few reasons why school should start later. For one, teenagers need more sleep than adults. Their brains are still growing and need time to rest. Starting school later would also allow students to get more exercise, eat a healthier breakfast, and be less rushed in the morning. This would lead to them being more alert and focused in class.
There are a number of reasons why school should start later. For one, students are not getting enough sleep. According to the National Sleep Foundation, teenagers need eight to 10 hours of sleep per night, but most are only getting seven. This lack of sleep is leading to problems in school, such as lower grades and higher rates of tardiness and absenteeism.
Another reason to start school later is that teenagers’ circadian rhythms are different from those of adults.
There are a few scientific reasons why school should start later. One reason is that teenagers’ brains work differently than adults’ brains. Teenagers need more sleep than adults, and they perform better in school when they get more sleep. Another reason is that teenagers are more likely to be involved in car accidents if they are driving to school early in the morning.
There is evidence that suggests that starting school later would be beneficial for students. One study found that students who started school later got more sleep and had better grades. Another study found that students who started school later were less likely to be obese.
There are a few benefits to starting school later for teachers. For one, it gives them more time to prepare for their classes. It also allows them to get more sleep, which can help improve their productivity and mood. Finally, it gives them a chance to relax and recharge before the start of the school year.
There are a number of reasons why school should start later for teens. One is that teens need more sleep than younger children or adults. Their bodies are still growing and developing, and they need more time to rest. Another reason is that teens are more likely to be sleepy in the morning because of their natural body rhythms. Starting school later would allow them to get more rest and be more alert in class.
There is a lot of research that suggests that later school start times can be beneficial for students. One study from the University of Minnesota found that when schools started later, students got more sleep, had better grades, and were less likely to be tardy or absent.
There are a few things to consider when making the decision to change school start times, such as how it will impact transportation and after-school activities.
There is no one-size-fits-all answer to this question, as it depends on the individual needs of students and their families. Some people believe that school should start later in the day, so that students have more time to sleep and are better rested for class. Others argue that starting school later would disrupt the morning routines of students and their families. Ultimately, it is up to local school districts to decide when classes should start.
There is a lot of research that suggests that later school times would affect sleep. One study found that students who had school start times after 8:30 am got significantly less sleep on school nights than students who had earlier school start times. The study also found that the students who had later school start times were more likely to be tardy, miss class, and have lower grades.
There are pros and cons to starting school later. Some of the pros include:
-Students would be more rested and alert.
-Teachers would have more time to prepare for lessons.
-Less rowdy behavior in class.
Some of the cons include:
-Later start times would mean earlier end times, which could interfere with students’ after-school activities.
-It may be difficult to get transportation companies to agree to later start times.