Sleeping enough makes attending school much better experience: It facilitates learning, improves mood and in a long term, sleep is also important for health and wellbeing: sleep deprivation that lasts months or years increases risk for variety of serious medical conditions, such as depression and diabetes.
Regardless of the importance of sleep, large portion of adolescents do not sleep enough. The recommended sleep duration for people aged 14-17 is 8-10 hours per night but over half of this age group does not sleep this much on weekdays.
There are several reasons why adolescents do not sleep as much as they should, some of which are in their own control and some which are not. Abstaining from drinking caffeinated beverages in the evenings, reducing the use of smartphones at night and trying to maintain schedule that leave enough time for sleep are good ways of improving sleep and many young people could do better with these things. However, sleep of young people is also challenge for biological and societal reasons.
Preference to sleep at certain time of the day is controlled by a circadian rhythm, roughly 24 hours long cycle that affects various things in our body and brain. This rhythm makes us feel energetic during the day and sleep during the night and it is maintained a biological clock residing in our brain.
Not everyone has similar biological clock. Actually, there is quite a bit of variation between people in how their circadian rhythm works. Some people tend to wake up early, be energetic in the morning and get sleepy early in the evening. Others would prefer to sleep late, are energetic in the evening and stay up late. Most are somewhere in between these extremes. Tendency towards certain kind of circadian rhythm is called chronotype. It is a trait that is heavily influenced by genetics and hard to change by yourself.
Age influences chronotype: one of the effects of hormonal changes during puberty is shift of chronotype towards evening. During adolescence and early adulthood people tend to be as evening types as they are ever going to be. During adulthood their chronotype starts to shift towards morning resulting most of the elderly being morning types. The practical effect of this shift is that many teenagers have trouble waking up early even if they did so without much hassle as children. This is not because of laziness – there has been a concrete change in how their biological clock works.
Evening chronotype is not a problem but it can become a problem if environment requires the person to wake up early. Unfortunately, this is a common occurrence: School start times dictate when adolescents should wake up and for many, this means waking up earlier than what their biological clock would prefer. Going to bed earlier may not help much as biological clock of evening types makes falling asleep early quite challenging as well.
The result is that many students are more sleep than awake for first hours of their schooldays as well as chronic sleep dept that is usually paid by sleeping in on weekends. This is not optimal for wellbeing or learning for that matter.
Maintain constant sleep scheduled and avoid things that disturb sleep alleviates the issue a little but simple way to help evening prone people to sleep longer is to gift them more of that precious morning sleep.
Delaying school start times could save sleep and increase vigilance for large proportion of students. There is active research going on about benefits of later school start times and though more studies would be welcome, the ones that are published report that even 25-minutes later school start time appears to increase sleep duration and alertness. Since school start times affect schedule of more than just the students, there certainly are challenges in implementing meaningful delays. However, more time to sleep would improve quality of life of many sleep deprived young people.
Nils Sandman, PhD
Post-doctoral researcher, University of Turku & University of Helsinki
Hirshkowitz, M., Whiton, K., Albert, S. M., Alessi, C., Bruni, O., DonCarlos, L., … & Neubauer, D. N. (2015). National Sleep Foundation’s sleep time duration recommendations: methodology and results summary. Sleep health, 1(1), 40-43.
Minges, K. E., & Redeker, N. S. (2016). Delayed school start times and adolescent sleep: A systematic review of the experimental evidence. Sleep medicine reviews, 28, 86-95.
Roenneberg, T., Wirz-Justice, A., & Merrow, M. (2003). Life between clocks: daily temporal patterns of human chronotypes. Journal of biological rhythms, 18(1), 80-90.