Teenagers need just as much sleep as children

How important is sleep in teenage years? It is well known that small children need a lot of sleep to get through the day. New research shows that teenagers are also susceptible to the consequences of a lack of sleep.

Parents, educators and teenagers themselves blame the media and technology for the fact that sleep deteriorates with the onset of puberty. Teenagers say they stay up late to manage the balancing act between social commitments, homework, extracurricular activities, part-time jobs and technology.

Very few people realise that there are also biological reasons for this change in sleep behaviour. When the release of puberty hormones begins, many adolescents experience «delayed sleep phases» - a preference for going to bed later. This phase delay involves a shift in sleep patterns of up to two hours compared to middle childhood. While sixth-graders go to bed at 9.24 pm on average, bedtime for twelfth-graders (aged 17 to 18) begins at 11.02 pm on average.

Parents should educate their teenagers about the health risks of sleep deprivation.

Dr Adriana Galván

This phenomenon is observed all over the world in people from different cultural backgrounds. So what does biology have to do with when we go to bed?

Firstly, melatonin - the hormone that signals when we are tired - is released later in the evening in teenagers than in adults. This makes it difficult for many teenagers to fall asleep earlier. Secondly, teenagers experience a change in «sleep pressure», i.e. the pressure or desire to fall asleep increases more slowly than in children. This leads to a higher tolerance for being awake. Because of these two factors, most adolescents can stay awake longer without feeling tired.
The problem, however, is that despite their greater tolerance for wakefulness, teenagers need just as much sleep as children - and nobody would want to discuss whether babies or toddlers need a lot of sleep. But how is a teenager supposed to get as much sleep as they used to if their body encourages them to stay awake longer?

The answer is simple: nature intended for young people to go to bed later, but also to get up later. However, modern society has thrown a spanner in the works of nature with early school start times. As a result, many young people stay up late on school days, don't get enough sleep and struggle to stay awake in class the next day.

Modern society has thrown sand into the gears of nature with the early school start times.

In a recent study, we found that poor sleep not only has a negative impact on teenagers' mood, but also on their academic performance and brain function. We interviewed a group of teenagers for a fortnight about their daily sleeping habits. We also collected information about their mood, academic performance, stress levels and general well-being.

We had expected that the results would be worse in all these areas for teenagers who got less sleep overall. Instead, we found that greater sleep variability was more detrimental than chronic sleep deprivation. Teenagers whose sleep behaviour varied significantly from night to night performed worse at school (as measured by their average grades) and showed less activity in the regions of the brain responsible for acquiring new knowledge. This phenomenon is known as «social jet lag» and refers to irregular sleep patterns. The term describes the different length of sleep on weekdays and weekends, but also reflects the daily variability of sleep.

In a second evaluation, we investigated the effects of everyday stress on the link between pronounced sleep variability and impaired brain function.
The results showed that teenagers took more risks in a computer game involving risky decisions after a very stressful day. They also recorded less activity in the insula - a brain region that plays a role in risk assessment. However, this effect only occurred in those teenagers who had slept too little the night before. This suggests that a lack of sleep can exacerbate the effects of stress on behaviour and, in particular, exacerbate bad decisions.

Irregular sleep is more harmful than chronic sleep deprivation.

It is a priority for parents to educate their teens about health risks such as substance abuse, unprotected sex and reckless driving. Unfortunately, the dangers of sleep deprivation are not among the things parents warn their teens about.

New parents are obsessed with the sleeping behaviour of their newborn babies. But over the years, this interest wanes. According to a large-scale study conducted by the National Sleep Foundation a few years ago, just under a third (29 per cent) of parents surveyed were aware of the disparity between the recommended and actual amount of sleep time for teenagers. This is a worrying lack of parental awareness of the extent of sleep deprivation in their teenage children.

But there is also good news: sleep habits can be changed. New research on teen sleep can help teens, parents and educators take control of sleep patterns so that teens get enough sleep. The first step is to educate about the importance of sleep and back this up with neurobiological research in teenagers. This is what our lab and labs around the world are working towards.

Good to know

  • As puberty hormones begin to be released, many teenagers develop a preference for going to bed later.
  • Teenagers have a higher tolerance for being awake, but they need just as much sleep as children.
  • Teenagers are susceptible to the consequences of sleep deprivation, both in terms of their behaviour and their brain development and function.
  • Irregular sleep patterns have a particularly detrimental effect on academic performance and learning.
  • Lack of sleep can increase the effect of stress on behaviour.
Dr. Adriana Galván  ist Forschungsprofessorin im Fachbereich für Psychologie an der University of California, Los Angeles. Ihre Forschung konzentriert sich auf die Entwicklung des jugendlichen Gehirns. Ihr besonderes Interesse gilt der Frage, wie die Reifung des Gehirns nach der Pubertät typische Verhaltensweisen von Erwachsenen wie Risikobereitschaft, Belohnungsverhalten, Exploration und Orientierung an Gleichaltrigen beeinflusst.  Adriana Galváns Forschung wurde im Rahmen des Jacobs Young Scholars Program gefördert.
Dr Adriana Galván is a research professor in the Department of Psychology at the University of California, Los Angeles. Her research
focuses on the development of the adolescent brain. She is particularly interested in how the maturation of the brain after puberty influences typical adult behaviours such as risk-taking, reward-seeking, exploration and peer orientation. Adriana Galván's research has been funded by the Jacobs Young Scholars Program.

Read more:

The topic of children's sleep is complex. We therefore dedicated an entire dossier to it in February 2015. Click here for the main article «Sleep! Little child! Sleep!». The 01/15 magazine can also be reordered .

  • Should children sleep with their parents? The family bed is controversial.
  • The four biggest myths about sleep
  • Can my child sleep too little? Questions for the sleep researcher
  • Is the mobile phone to blame for the sleep disorders?

Jacobs Foundation

As one of the world's leading charitable foundations, the Jacobs Foundation has been committed to promoting research in the field of child and youth development for 25 years. The Foundation aims to provide sustainable support for future generations by improving their development opportunities.