By Diana Zuckerman, Ph.D.
National Center for Health Research
In the 1950′s and 1960′s, most schools started between 8:30-9:00 and many students barely stayed awake all day. By 2000, many high schools were starting at 7:30 or earlier, and a growing number of studies showed that these early school schedules can undermine teenagers’ ability to learn, to drive safely, and to get along with others. They can even increase the likelihood of smoking, drug abuse, and teen pregnancy.
Some school districts have responded by starting schools a little later, but traditions are difficult to change and many have been reluctant to have high schools start later in the morning and end later in the afternoon. How important is it to start high schools closer to 9 am?
Starting at puberty (and as early as ages 8-12), many children’s biological “circadian” rhythms change. They start staying up later at night and sleeping later in the mornings. These pubertal changes tend to start earlier for African Americans than for whites, so bedtimes may be a problem for many middle-school children as well, especially African Americans. There are individual differences, but most adolescents “naturally” feel awake later at night, making it difficult to go to sleep before 10 p.m.
Sleep researchers have found that most adolescents and adults need more than 9 hours of sleep: we can “get used to” less, and we might think we’re adjusted to less, but our brains and bodies won’t be doing as well with less sleep. Those of us who routinely get 6 hours of sleep or less are functioning just like someone who stayed up 48 hours straight after getting 8 hours of sleep on a regular basis.
Learning. Falling asleep in class makes it impossible to learn, but that is not the biggest problem for sleepy students. More common, less noticeable, and therefore much more of a problem is that students who don’t get 8-9 hours of sleep find it more difficult to concentrate in class and their ability to remember what they read or hear is impaired.
Safety. Sleep deprivation is similar to alcohol in its effect on judgment, reaction time, and driving skill. And like alcohol, the teen or adult impaired from lack of sleep is unlikely to realize it. Sleep deprivation is a problem for all drivers, but especially inexperienced ones. Falling asleep at the wheel can also be fatal for the driver, passengers, and bystanders. Remember, a one-second delay in pressing the brake while going 60 mph will send your car an additional 88 feet!
Smoking, Drinking, Sex, and Drugs. The same impaired judgment that can cause car accidents can also result in making bad choices. Teens are easily swayed by peer pressure, and lack of sleep makes them even less able to “just say no” or think ahead about negative consequences. This can result in all kinds of problem behaviors. The fact that high schools end early and many teens are unsupervised from approximately 2:30 until 5:30 p.m. (even later in many suburbs) also creates the opportunity to make bad choices. Ask your local police department when teens are getting in trouble and they will inevitably talk about the unsupervised afterschool hours.
Teens use caffeine, nicotine, and other stimulants to stay awake, and the more they use, the later they stay up and the more tired they are when they have to wake up for school in the morning. Soft drinks such as Mountain Dew and Surge have even more caffeine than coffee or cola.
Conflicts with Family and Friends. Everyone knows that tired babies are cranky. Research shows that tired adolescents and adults are also cranky, easily frustrated, and overly emotional. This can contribute to constant tension between family members.
Obesity. Teens who get less sleep are also more likely to be overweight or obese. When teens don’t get enough sleep, their bodies go through hormone changes that make them more tired and hungry. Because they are more tired, they often exercise less and drink more sugar-filled caffeinated drinks. This starts a vicious cycle of weight gain, which leads to stress, which leads to sleeping less.3
You don’t need to be a research whiz to get the picture: kids need to get up before dawn to get to school on time. They have trouble paying attention in class and may be short-tempered with teachers and other students. After school, they may have a job, athletics, or spend time with their friends. After dinner, they may finally do their homework (they feel awake and productive, but they unfortunately aren’t, so it takes longer), continue their part-time jobs, or be with their friends. By 9:00 p.m., when they should be going to sleep to get the 9 hours of sleep they need, they are wide awake. So they stay up until 10:30 or later (perhaps much later), virtually guaranteeing that they will be sleep deprived when they get up at dawn the next day.
What if school started later?
Researchers wanted to see what would happen if the school day were to begin later. Would the teens simply stay up and wake up even later than before or would they get more rest and perform better? Administrators at a small private (mostly boarding) school in Rhode Island were willing to be part of the experiment and changed the morning start time from 8 a.m. to 8:30 a.m. What the researchers found was that students began to sleep more, reported feeling tired less often, were less likely to miss or be late to their first class, and ate more breakfast. In order to compensate for the later start time, the school cut 5-10 minutes from every class and activity. The change meant students had slightly less time in the classroom, but the tradeoff was improved attention during the school day.
Unfortunately, most schools across the country start much earlier than 8:30. This is often because they need to coordinate bus schedules across a district that has elementary, middle, and high schools. It is also because many parents and coaches are afraid that afterschool sports and other programs will run too late or have to be eliminated. One solution is to make the changes to school start times at a state level in order to coordinate afterschool activities and sports throughout the state.
This article was updated in 2015.
Getting up on the wrong side of the bed: sleepiness, behavior problems, and obesity in children and teens
What you can do to improve your sleep and your health
Young children and screen time (television, DVDs, computer)
Workshop on the sleep needs, patterns, and difficulties of adolescents. Board on children youth and families. National Academy of Sciences. 2000. http://www.nap.edu/openbook.php?record_id=9941&page=16