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Adolescents and Sleep Deprivation: AAP Recommends Delaying School Starting Time

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This is a topic that has been bugging me ever since I read the chapter in Nurture Shock on The Lost Hour – schools are starting too early and our teenagers are not getting enough sleep.

Recently, the American Academy of Pediatrics released a new policy statement recommending that middle and high schools delay the start of class to 8:30 am or later. Comments from a number of readers of Scientific American were up in arms over this suggestion. They felt that the problem was not that schools were starting too early but that teenagers just needed to be more disciplined about sleeping earlier and getting out of bed earlier. The sentiment seemed to be that we would be “giving in” to unruly, lazy teenagers who have simply developed bad sleeping habits and just needed to change them. It made me wonder if they had actually even read the article.

Teenagers get a bad rap. There is a stereotype about them and it’s not a nice one. The picture that’s painted is of a group of individuals who are self-centered, obnoxious, rebellious, out of control, and generally up to no good. But as much as we would like to blame them for their sleep woes, I’m afraid that the science actually supports them on this one…

Teenagers Have Altered Circadian Rhythms

Studies show our biologic clocks change with puberty. Many teens are not ready to fall asleep until at least midnight or later. However, they still need eight or nine hours of sleep per night, and would normally awaken at 8-10 a.m. or later.

This tendency in teens and young adults is called delayed sleep phase, and may interfere with daytime activities such as school. For this reason, many school systems around the country are adopting later start times for high schools and finding that this results in better scholastic performance. – UNM School of Medicine

What are Circadian Rhythms?

Also dubbed the “body’s clock”, the circadian rhythm is a 24-hour cycle that tells our bodies when to sleep and regulates many other physiological processes. This internal body clock is affected by environmental cues, like sunlight and temperature. In the teenage years, this sleep-wake cycle can be moved up to 2 hours later.

Changes to this circadian rhythm occur during adolescence, when most teens experience a sleep phase delay. This shift in teens’ circadian rhythm causes them to naturally feel alert later at night, making it difficult for them to fall asleep before 11:00 pm. Since most teens have early school start times along with other commitments, this sleep phase delay can make it difficult to get the sleep teens need — an average of 9 1/4 hours, but at least 8 1/2 hours. This sleep deprivation can influence the circadian rhythm; for teens the strongest circadian “dips” tend to occur between 3:00-7:00 am and 2:00-5:00 pm, but the morning dip (3:00-7:00 am) can be even longer if teens haven’t had enough sleep, and can even last until 9:00 or 10:00 am. – Sleep Foundation

The Role of Melatonin

One of the hormones that controls our circadian rhythm is called melatonin. It helps to regulate the sleep–wake cycle by chemically causing drowsiness and lowering the body’s temperature. In teenagers, the nightly schedule of melatonin is produced later than it is for younger children and adults, making it harder for them to fall asleep early.

Teenagers Start School Earlier

The teenage years are also the time when adolescents begin secondary school which usually has an earlier starting time. The need for an early start causes a disruption to their normal circadian rhythms and a growing body of research is demonstrating that this can have adverse health effects, like increasing the chances of cardiovascular events, obesity, and a correlation with neurological problems like depression and bipolar disorder.

No wonder our teenagers are often moody and snarky. They are sleep deprived!

Sleep is Important!

Sleep deprivation has significant consequences:

  • it decreases performance and alertness – reducing your nighttime sleep by as little as one and a half hours for just one night could result in a reduction of daytime alertness by as much as 32%
  • it causes memory and cognitive impairment affecting your recall, your judgement, and your ability to think and process information.
  • it reduces quality of life and contributes to the symptoms of depression
  • it increases the risk of accidents – both occupational and automobile injuries
  • it increases your risk of other health problems, such as heart problems, high blood pressure, stroke, and diabetes; and it may increase risk of death

Sleep deprivation is especially a concern for children who are still growing and developing. If they don’t get enough sleep, a lot of things start to go wrong.

Starting School Later

“research is clear that adolescents who get enough sleep have a reduced risk of being overweight or suffering depression, are less likely to be involved in automobile accidents, and have better grades, higher standardized test scores and an overall better quality of life.” – Judith Owens, paediatrician.

According to Scientific American, the later classes begin, the more academic performance improves. Attendance goes up, teen depression goes down, and fewer student drivers get into car crashes.

The results of a 3 year research study, conducted with over 9,000 students in eight public high schools in three states, reveal that high schools that start at 8:30 am or later allow for more than 60% of students to obtain at least eight hours of sleep per school night. Teens getting less than eight hours of sleep reported significantly higher depression symptoms, greater use of caffeine, and are at greater risk for making poor choices for substance use. Academic performance outcomes, including grades earned in core subject areas of math, English, science and social studies, plus performance on state and national achievement tests, attendance rates and reduced tardiness show significantly positive improvement with the later start times of 8:35 am or later. Finally, the number of car crashes for teen drivers from 16 to 18 years of age was significantly reduced by 70% when a school shifted start times from 7:35 am to 8:55 am. – University of Minesota (February, 2014)

Further Reading:

Published by Shen-Li

SHEN-LI LEE is the author of “Brainchild: Secrets to Unlocking Your Child’s Potential”. She is also the founder of (a website on parenting, education, child development) and (a website on Right Brain Education, cognitive development, and maximising potentials). In her spare time, she blogs on Forty, Fit & Fed, and Back to Basics.

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