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Monday, October 13, 2014

Delaying School Start Times for Sleep-Deprived Teens

From Science-Based Medicine

By Clay Jones
October 10, 2014

In August, a new policy statement from the American Academy of Pediatrics was published which tackled the widespread problem of insufficient sleep in our adolescent population. They even went so far as to label insufficient sleep as “one of the most common, important, and potentially remediable health risks in children.”

The statement, which gave a number of recommendations on how to address the problem, made the news rounds primarily because of the call for schools to delay start times until at least 8:30 AM.

I wrote about pediatric sleep in March for a post on the potential link between some sleep disorders in children, specifically nightmares and night terrors, and the development of psychosis. Those claims are suspect but please read that post for a review of what sleep is, why we need it, and what can go wrong with it in children of all ages.

For this post, my focus will be on adolescent sleep specifically, and on the role of delaying school start times in improving a variety of health parameters.

What are the common adolescent sleep challenges?

The typical modern teenager faces a variety of challenges to consistently obtaining a full nights sleep, which is considered by most sleep experts to be in the 8.5 to 9.5 hours per night range. This doesn’t mean that every teenager will fall apart if they only get 7 hours of sleep each night, but sub-optimal sleep can adversely affect school performance in many, and even lead to long-term health problems in some children who establish such a pattern during these pivotal years.

Hold that thought for now, however.

One obvious reason for insufficient sleep in teenagers, at least it is likely obvious if you have one of your own or have ever spent more than two minutes near one, is technology. Most older children have electronic media in their rooms, if not attached to their bodies in the form of a smart phone. 24-7 access to the internet and social media is a commonly cited impediment to sleep onset.

The increasing availability and popularity of energy drinks containing absurd amounts of caffeine among adolescents likely also plays a role as both a coping strategy for daytime fatigue resulting from insufficient sleep, and as a cause of it. In fact, I think I’ve just come up with the topic for my next post.

In addition to poor sleep hygiene and the intake of stimulants, the final impediment to a full night’s sleep addressed in the AAP statement is much more insidious. From a biological perspective, among the many changes that a child undergoes with the onset of puberty is an alteration of the internal circadian rhythm and sleep drive.

Most adolescents gradually shift towards favoring staying up later and subsequently sleeping later. Even without the influence of social media and caffeine, teens often have difficulty falling asleep before 11 PM and waking before 8 AM.

With chronic insufficient sleep, a teen may not feel truly alert until after 10 AM. Again, there is variability between individuals, but this affects the vast majority of even healthy teenagers.

It is the combination of multiple factors, such as those discussed above, but also including the need to wake up earlier on weekdays for school, that leads to a build up of daytime fatigue. Many teenagers will thus sleep later on the weekends or holidays. While this is a manifestation of their underlying biological sleep preference, it is also driven by sleep pressure accumulated during the week.

Attempting to catch up on the weekends doesn’t actually solve the problem and may make it harder for teens to adjust sleep cycles over the long haul.

Again, this problem exists in almost all healthy teenagers. But many medical conditions, and the treatments for them, also negatively impact sleep. Poorly controlled asthma is probably the most well known sleep disrupting diagnosis because symptoms like cough and wheeze are often worse at night and can occur frequently. Some children with asthma present with persistent nighttime cough and interrupted sleep as their primary complaint.

The effect on parental sleep and well-being is also well known. Anxiety and stress related conditions are also common in the adolescent population, and these can both cause and be exacerbated by poor sleep. Not surprisingly, the socioeconomic milieu in which children find themselves in impacts the quality of their sleep as well, with kids in low income families having the toughest time.

How common is insufficient sleep in adolescents?

According to the technical report that accompanied the AAP policy statement, the concern that teenagers are not getting enough sleep is based on solid epidemiological data, and is likely even underestimated because self-reporting tends to overestimate actual hours slept. With that in mind, the National Sleep Foundation Sleep in America Poll revealed that 3 out of 4 kids average less than 8 hours of sleep each night by senior year.

This poll, and other studies presented in the report, uncovered the fact that most teens feel tired at school with many reporting episodes of falling asleep in class.

Furthermore, most teens feel the need to compensate with stimulants and extra weekend sleep. Unfortunately, also per a number of surveys, parents are largely unaware of these issues and believe that their teenage children are getting the recommended amount of sleep.

How does insufficient sleep harm adolescents?

The list of potential harms from insufficient sleep in the adolescent population is large and varied, and includes both immediate and long term effects. The AAP report highlights three categories of negative effects: Physical health and safety, Mental health and behavior, and School performance. I’ll highlight some of the major potential consequences in each.

Obesity and long term cardiovascular events like heart attacks and stroke have been linked to insufficient sleep starting in the teenage years. More acute is the major issue of “drowsy driving” and the risk of motor vehicle accidents, with 50,000 fatigue-related accidents occurring each year involving a driver under the age of 25. Increased consumption of caffeine, and potential associated toxicity, is clearly linked to poor sleep, but use of prescription stimulants that have been diverted from their intended indications is also a concern, although evidence is lacking at this time.

Teenagers with chronic inadequate sleep are more likely to have anxiety conditions and depression. They are also at risk for difficulties with impulse control and self-regulation, increasing risk-taking behaviors. Poor sleep can also interfere with the ability to process stress, which can exacerbate the likelihood of illness and maladaptive coping strategies.

And, not surprisingly, adequate sleep plays an important role in cognitive function, memory and attention. Poor sleep thus can interfere with academic success, increase missed days of school and lead to higher rates of dropping out.

What can we do about insufficient sleep in adolescents?

The AAP’s big push is for schools across the country to delay start times to at least 8:30 AM. This isn’t a new concept, with some experts and parent groups calling for a return to later start times since the early 1990′s, but it still represents an important advance in advocating for adolescent health. The report provides compelling evidence of benefit, evidence that is available because over 200 school districts have already made such a change in the United States and later start times are more common in other countries. This study even looked at the opposite, following 40 students who were forced to transition to starting school an hour earlier.

The available research is more than adequate to answer some of the questions that have historically been raised. At the onset of the “Start School Later movement“, evidence was lacking regarding school performance benefits. It’s quite clear now, however, that students benefit across the board. Rather than simply staying up later in response, significant numbers of kids will increase their average sleep into the recommended range.

Other outcomes that have now been shown to improve in multiple studies include decreased self-reports of fatigue and improved academic performance such as improved grades and higher reading and math scores.

When 18,000 high school students in Minneapolis had their start time shifted over an hour later, they got more sleep, called in sick less often and had fewer dropouts. We also have data showing improvements in mood and motivation, and even a decrease in car accidents. If only looking at the evidence of benefit, it truly appears to be a no-brainer.

But things are rarely so simple. The current most common school start times, usually somewhere in the 7 o’clock hour, may have only been in vogue for a few decades, but they are well established at this point. And although many school districts have successfully made a change, the logistics to consider are considerable. Historically, calls for making school start times more physiologically appropriate have fallen on deaf ears, primarily because of concerns regarding expense, transportation and loss of time after school for athletic and club activities, student jobs and homework.

Some parents also depend on older children to watch younger siblings in the afternoons, which would be difficult if school ends later in the day.

Unfortunately there aren’t any studies investigating these concerns in districts that have shifted start times. So I am personally a bit hesitant to come down too hard on the districts that are dragging their feet. This change may be more or less reasonable depending on the community, but I do feel strongly that this should be taken seriously and the feasibility looked into.

The AAP statement points out that many communities have come up with creative solutions these concerns, and that there is at least anecdotal evidence that many of the fears haven’t materialized.


Sleep is an important concept across the spectrum of age, and insufficient amounts can have a variety of negative health effects. This is perhaps even more critical a concern in the adolescent population. A growing body of evidence continues to reveal the damage that poor sleep can cause in teenagers, just how common the problem is and the unfortunate lack of awareness among parents and caregivers.

And, patterns of behavior learned during this pivotal period of development may be setting teens up to have health problems years down the road.

There are many ways to chip away at the problem of inadequate sleep, such as setting reasonable limits on the use of technology and educating teenagers on other ways to improve sleep hygiene, such as avoiding excessive intake of energy drinks and other highly caffeinated beverages. There is also a substantial literature in support of pushing the start of school days back in order to allow for extra sleep on weekdays.

This change may come with some challenges, but it is almost certainly worth a potentially difficult transitional period.

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