Skip to content

Teenagers and Sleep – Dr. Irena Keller on How Teenagers are Wired Differently

March 11, 2016

IMG_3061Student stress, homework overload and the inability for teenagers to get a full night’s sleep have been hot topics in recent years. Our next featured interview focuses on sleep, and the critical importance for childhood development. To learn more we spoke with Tri-Valley resident and UC Berkeley biological and developmental psychology PhD graduate, Dr. Irena Keller. Dr. Keller is currently an Adjunct Professor in the Department of Child and Adolescent Development, Connie L. Lurie School of Education, San Jose State University. What sparked your interest in sleep and lead you to dedicate your PhD research to the impact of sleep?

Irena Keller: “It started with my kids! They wouldn’t sleep when they were babies and I found the recommendations for parents about how to take care of children at night were so varied – co-sleeping vs. non-co-sleeping, what is culturally-based vs. what is biologically-based – people have a lot of misunderstandings about sleep. As I started to explore sleep and the impact on brain development, memory, and learning I started looking at older children and it was fascinating. Our society doesn’t take sleep as seriously as it should, and the importance of sleep in the development of children.

“Most of the population is sleep deprived. For children, and in particular teenagers, there is a biological shift when puberty hits resulting in children needing to sleep later. The circadian rhythm of teenagers shifts – they go from being early birds biologically to night owls! It’s not that teenagers don’t want to wake up early, it is difficult for them. The hormones that help you to wake up and go to sleep work on a circadian rhythm; in the morning you need cortisol to wake up and at night you need melatonin to fall asleep. Teenagers get cortisol much later in the morning and melatonin much later at night. When teenagers don’t want to go to sleep at night it’s because of how they are biologically wired.

“Unfortunately as children progress through school, the start time for school tends to be earlier, which is the opposite of what should happen based on the biology of teenagers. Schools also have a zero period for students in extracurricular activities like band or leadership, making the problem even worse.” What is happening when you are sleeping that makes sleep so important?

Keller: “It’s not just sleeping that is important, but the different stages of sleep. If you wake up during the night you may not complete all of the sleep cycles that you need, and your sleep will be less effective. The different stages of sleep play different roles in memory consolidation, emotional problem solving and learning reinforcement.

“For example, there was a study of students performing a blind typing task. The first group of students took a lesson and then went for a nap, the second group of students kept working on the lesson and the third group was allowed to do something else after completing the lesson. All three groups were tested and the group that took a nap performed the best, even better than the group that kept practicing. What is amazing is that the group that took a nap was still practicing the exercise while sleeping, so they were better prepared after waking up. Researchers were able to show with an fMRI how the brain reinforces learning while asleep. Researchers recorded that the brain activity connected with learning the task while awake was the same as the brain activity during sleep, except sped up. The brain was practicing the task over and over during sleep. During sleep you consolidate, and also forget, so that the important details are reinforced.

“Research also demonstrated that sleep plays a role in emotional healing. Victims of PTSD do not experience proper sleep patterns, because of nightmares some of the stages of sleep are missing or are incomplete. It’s as though PTSD victims relive the same painful experience over and over because the emotional healing aspect of sleep is not working. The brain is not separating memories from emotions. What should happen is that you are left with the memory, but without the painful emotion.” How are sleep experiments conducted?


Dr. Matthew Walker

Keller: “The sleep experiments I mentioned were performed at UC Berkeley in Matthew Walker’s Sleep and Neuroimaging Lab. The lab includes a room for sleeping as well as an fMRI machine for measuring brain activity during sleep. For experiments involving sleep deprivation the research assistants ensure you don’t fall asleep before the test. The subjects of the tests will typically not realize that they are sleep-deprived and will believe they are doing much better on the tests than they really are, and will be insistent that they are fine!” Is it true that you can “catch up” on sleep? Or is that a myth?

Keller: “You can catch up on sleep to a point: think of sleep as something you need to fill-up. If you don’t have enough sleep you will have the need to fill your body with sleep. The problem with ‘catching up’ after several days is that you have basically wasted those days in terms of memory and learning. Sleeping not only consolidates what you’ve learned, but prepares you to learn, by consolidating and cleaning (forgetting) your brain is open to receive new information.” What can educators and school districts do to take action based on this research?

Keller: “The start time for school needs to be developmentally appropriate. Most teenagers are sleep-deprived and it’s not just because of gadgets or stubbornness, but because of their biology and being required to wake up early for school.

“It’s no surprise that when teenagers go to school they are sleepy, they are tired, they can’t learn as well, they can’t remember what they learned the day before, and they are not as safe driving to school. As I noted earlier, sleep helps with emotional healing so sleep-deprived teenagers also have emotional challenges. Research has shown that the judgement of facial expressions can be impaired by sleep deprivation, misperceiving a person as being aggressive when they are not. A lack of sleep can cause more negative thoughts, anxiety, and even depression.

“Some states and districts are shifting the start of school to be later, but change is difficult. Bus schedules are hard to change, parents need to get to work and schools get set into a schedule.” What can parents do to help their children, especially their teens, get enough sleep?

Keller: “Work with your children to organize their morning tasks the night before so they don’t have to get up as early; prepare everything you can the night before.

“Melatonin, the hormone you need to fall asleep, is affected by light. A few hours before sleep you want to reduce the light going into your eyes which is a problem because of all the devices with light we use today. What I do with my kids is ask them to turn down the brightness or change the background to a ‘night mode’.

“There are even light boxes, very powerful lights used for therapy, that can help you wake up in the morning and can even shift your circadian rhythm earlier. At night you want the opposite and eliminate light. It’s likely not realistic to completely take away gadgets – teenagers will find a way – but try to reduce the light from gadgets.

“Finally, parents need to understand that teenagers are biologically different and that it is difficult for teenagers to fall asleep and wake up early.”



Comments are closed.

%d bloggers like this: