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Teen Sleep

Teenagers aren't lazy – they're sleep deprived. Find out why early school start times and delayed biological rhythms can make a good night's sleep difficult for young adults



Labelling individuals who prioritise their sleep as 'lazy' rather than 'sensible' is largely the result of modern-society valuing short-term financial gains over health and wellbeing. If politicians and companies were focused on maximising productivity in the long-run, then a well-slept, happy and healthy population would be key. (You can read more about the economic costs of a sleep-deprived society in a future post).

While a typical work day involves waking-up at the crack of dawn, worshipping coffee and replying to stress-inducing emails late into the night, the situation for children and young adults isn't much better. In fact, for the majority of teenagers, getting 9 hours of sleep per night may be unachievable for two key reasons.


Unlike adults, who need between 7–9 hours of sleep per night, young adults aged between 14 and 17 years old need 8–10 hours.


Early School Start Times

The average UK secondary school starts at around 8.30am, while US schools have an even earlier start time of 8.00am.

For teens getting the bus, this means a wake-up time of 6.30am or earlier if they are to shower, get dressed and have breakfast before heading to the bus stop – usually in the dark – for 7.30am. This will be even earlier for anyone in a rural area or in a big country like the US, where journeys are longer and schools are further away.

Consequently, in order to get 9 hours of sleep, teens would have to be ready for bed by 9pm and asleep by 9.30pm.


Teen Biology

You may think that getting into bed by 9pm sounds like a piece of cake, but if you're familiar with teenagers, or if you're a teen yourself, you will know that this is far from the truth.

This is because during the teenage years, your 'biological clock' is delayed by about two hours, meaning teenagers naturally want to stay-up late and sleep-in late.

Expecting a teen to sleep at 9.30pm, is like expecting an adult to sleep at 7.30pm. In the same way, asking a teen to wake up at 6.30am would be equivalent to asking an adult to wake-up at 4.30am – it's no wonder that 20-30% of high school students report falling asleep in class each day!

This biological shift occurs in all teenagers regardless of country, culture or societal norms. By forcing our teens to get-up at 6.30am – a time that is still their biological night – we are depriving them of the crucial REM (rapid eye-movement) sleep that occurs in the latter half of the night.

Ironically, this REM sleep is essential for learning, memory, emotional processing and impulse-control – all things that are crucial to the developing brain (you can read more about the role of sleep in learning and memory in this post).

Perhaps many of the complaints made by parents and teachers regarding distractibility, irritability and laziness are really just signs of sleep deprivation. Indeed, the high levels of mental illness and suicidality in the teenage population have been linked to the high levels of sleep deprivation.


To make matters worse, due to the sleep deprivation that accumulates over the school week, many teens will attempt to catch-up on sleep over the weekend. As a result, it may be quite normal for teens to sleep half the day away, hence the stereotype of 'lazy'.

Unfortunately, just as teens begin to settle into their natural rhythms, it's Monday again, and they're hit with a double dose of social jet-lag.

Social jet-lag refers to the fatigue that arises when an individual's weekday and weekend sleep times differ.


Interestingly, researchers are still unsure why teenage rhythms shift in this way, but some think it may help in the journey to independence.

During the teenage years, peer-relationships take precedence. If all the teens are up at the same time while the adults are sleeping, then they have more freedom to explore and interact with a variety of peers, which in turn helps in the formation of new social bonds and learning experiences.


Thankfully, as research progresses, we are starting to see conversations between scientists and policy-makers. In the US, the desire for happy and healthy teenagers has led to the beginnings of change (find out more at and

Indeed, trials have demonstrated that later school start-times can have huge benefits for the younger generation, including improved academic performance, reduced anxiety and depression, reduced acts of aggression and delinquency, and even decreased car accidents.


To help sleepy teens, we can do a number of things (you can read more sleep tips in a future post):

  • Understand! Hopefully articles like this will help to reverse the 'lazy' stereotype and open up an interesting dialogue between teens, parents, educators and policymakers. Talking about the importance of sleep and acknowledging the difficulties teens face is a great starting point for change.

  • Consistency is key. Don't overdo it at the weekend, or you'll suffer for it on Monday. Try to set a consistent and reasonable bedtime that allows for as close to 9 hours as possible.

  • Limit caffeine and energy drinks in the evening.

  • Create a bedtime routine. Try to start winding down an hour before bed. Replace stress and sources of blue-light with enjoyable, relaxing activities.

  • Create a good sleep environment. Try and keep the bedroom dark, cool and tidy. Avoid doing your work in bed to avoid associating your bed with stress and activity. Keep the phone out of the bedroom, or at least turn off your notifications as these can disturb sleep.


For teenagers, 9-hours of sleep per night may be an unachievable goal in light of early school start times and delayed biological clocks. Indeed, the stereotypically 'lazy' teen is more likely to be a sleep-deprived victim of an unsympathetic society. Consequently, if we want our future generations to be happy, healthy and ready to learn, then we must let them sleep.



Bryant, N. B., & Gómez, R. L. (2015). The teen sleep loss epidemic: What can be done?. Translational Issues in Psychological Science, 1(1), 116.

Danner, F., & Phillips, B. (2008). Adolescent sleep, school start times, and teen motor vehicle crashes. Journal of Clinical Sleep Medicine, 4(6), 533-535.

Fitzgerald, C. T., Messias, E., & Buysse, D. J. (2011). Teen sleep and suicidality: results from the youth risk behavior surveys of 2007 and 2009. Journal of clinical sleep medicine.

Walker, M. (2017). Why we sleep: The new science of sleep and dreams. Penguin UK.


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