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Sleep and Test Prep: What Parents Should Know

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Kristan Siegel, a high school math teacher in Houston, sees first-hand the effects of sleep deprivation on test-taking teens.


“When students don't get adequate sleep (especially during exams week) I notice their grades suffer. When they come to take a quiz and they're tired and distracted, they don't recall the material as well and will earn a lower grade," she says.


Weekly quizzes, finals, standardized tests, college entrance exams, for better or worse, test taking is part of teens' school year experience. Unfortunately, so is not getting enough sleep.


When those two realities collide, the result is often increased test anxiety and poor test performance.


Teens Cut Back on ZZZs

“Cutting back on sleep is detrimental to your brain function. It's really as simple as that," says Michael Scullin, the director of the Sleep Neuroscience and Cognition Laboratory at Baylor University.


During exam week, teens shorten their sleep by more than 17 minutes on average per night, according to a study published in the Journal of Sleep Research that tracked the sleep habits of high school seniors. This is on top of the hour per night of sleep teens lose during the school year from all the other time pressures they face.


A more recent survey by Sleep Number and GENYouth found that 71 percent of all middle and high school students start their school days with a sleep deficit of 1.7 hours on average. By the end of the week, they've lost the equivalent of a full night's sleep.


Sleep's Role in Test Taking

A good night's sleep lays the foundation for good test taking, says Scullin. For teens that means getting the recommended nine hours a night.


In Scullins' study published in Teaching of Psychology, he found incentivizing a small group of college students to sleep eight hours a night during exam week resulted in a four-point grade boost compared to those who didn't get as much sleep.


“The more they slept, the better they were able to do on their final exams," he says.


Sleep affects how well your teen will perform on tests, and academics in general, in three critical ways.


  1. Sleep helps you stay focused. Tests can be both complex — long reading passages and complicated math equations — and last for several hours. If your teen doesn't sleep enough, he or she will run out of mental steam during testing. “Lack of sleep, or even a reduction in sleep, impacts the systems of your brain that allows you to sustain attention," says Scullin.

  2. Sleep reinforces classroom learning. Sleep consolidates what is learned the previous day. “If you're studying for a test and then you cut back on sleep, you're actually cutting back the exact process that takes the information you learned during the day and reactivates it, re-processes it and re-integrates it into your knowledge stores," says Scullin. In other words, you won't remember all that studying if you're not sleeping well too.

  3. Sleep reduces test anxiety. When you're sleep deprived, you're more emotionally reactive and less able to handle daytime stress. “There's a lot of test anxiety that occurs before tests and sleep restriction is something that sets the stage for that," says Scullin. “What people do really need to understand is that there's this bidirectional association: If you're feeling stressed, that makes it harder to sleep. But if you're not sleeping well, that's going to make your stress heavier during the day."


A Better Way to Test Prep

To study for tests, teens often worsen their sleep deficit, from staying up later than normal to pulling all-nighters. You probably did that as a teen, too, but it's not something you want your kid to emulate.


“Cramming is a solution to retain information five minutes into the future. It's not a way to retain information for a test," says Scullin.


Research shows that to improve academic performance, do the exact opposite of those bad cramming habits, says Scullin.


Instead, here are some tips to help teens do well on that next exam. Don't be surprised if these steps help them sleep better, too.


  1. Focus on time management. Teens need to plan and prioritize their school work, homework, extracurricular activities and social lives. “If you manage your time well, then you're going to sleep well at night. And if you sleep well at night, you're going to manage your time more efficiently the next day," says Scullin. Limiting screen time can help them focus on what matters. Limiting blue light exposure from electronic devices an hour before bed can also help them fall asleep better. Scullin suggests downloading apps that limit time spent on social media and electronics. Also, switch devices to "night mode" to help reduce blue light before bedtime.
  2. Space out studying. The brain retains information better if information is repeated in shorter intervals. “The best way is to space out your studying across several days," says Scullin.

  3. Test first. It's important for teens to test their knowledge before an exam. "Testing yourself rather than rereading your notes or just

    highlighting text; oh my gosh, that is how you learn," says Scullin. He suggests covering up notes and seeing what is remembered about a given topic. Answer out loud. When using flashcards, don't immediately flip them over. “Struggle with it for a little while. That struggling process actually helps," says Scullin. Study what isn't already known and then test again, later.

  4. Sleep on it. A study published in Psychological Science found breaking up studying with sleep helps reduce the time it takes to learn something by half and improves retention up to six months later compared to research participants who only studied during two different intervals in the same day.


Scullin shares this before-the-test action plan with his college students:

  • Study the evening before the test

  • Get a good night's sleep

  • Review the material the morning of the test


“It combines the benefits of good sleep, it combines the benefits of testing and it combines the benefits of spacing effect," says Scullin.


So if you want your teen to do better academically and emotionally year-round, share these tools to support better sleep, too.


Like nutrition and exercise, quality sleep is essential for optimal health and performance. To ensure kids and their families understand the impact of quality sleep and have the tools to achieve it, Sleep Number is committed to improving 1 million kids' lives through better sleep by 2025. To learn more, visit the Sleep Number Social Impact page, and find your Sleep Number® setting for your best possible night's sleep.

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