What’s Keeping Teenagers Up?

Sleep is vital for cognitive, physical, and emotional functioning, and receiving inadequate sleep is associated with various physical and mental health problems. Having adequate sleep is particularly important for teenagers. Not only are adolescents coping with increasing academic and social demands, they are also experiencing a period of rapid cognitive and physical development. While sleep needs do vary from person to person, the National Sleep Association recommends that adolescents sleep for 8 to 10 hours per night.

If sleep is so important, why are many adolescents not achieving the recommend nightly sleep duration, leaving them more vulnerable to health, academic, and emotional difficulties?

Early school start times do play a role. A 2014 Melbourne study found upon entering a two-week vacation period after the conclusion of the school term, adolescent bedtimes and risetimes became later, and sleep duration increased substantially by nearly an hour on average. However, despite longer sleep duration, sleep quality remained high during the first few non-school days. This suggests that adolescents may have received insufficient sleep and therefore accrued a sleep debt during the school term.

In addition to school times, adolescents’ behavior before bed could also matter. In recent years, more and more adolescents have regular access to portable technologies such as smartphones, tablets, and laptop computers. Some studies linked the use of these technologies with negative outcomes on sleep. However, some questions remain as to why such relationships exist.

Australian researchers wanted to learn more about what kinds of pre-bedtime activities contribute to poor sleep among teens, and also, identify any behaviors that may promote better sleep. They looked at 25 activities that adolescents typically do in the hour before bed, such as sending e-mails or text messages, exercise, snacking, spending time with family or friends, playing video games, reading, listening to music, and using social media.

They then examined how each of these activities related to sleep, during both the school term and vacation period, taking into account chronotype – that is, whether teens tend to be more alert later in the evening (“night owls”) or more alert in the morning (“morning larks”). Sleep was measured objectively through a watch-like device that measures sleep and wake patterns. The study involved 146 adolescents aged 16-18 years.

Surprisingly, most pre-bedtime activities in their study had little effect on sleep duration or quality. The most important factor affecting sleep was the teenagers’ chronotype. Night owls tend to stay up later regardless of their bedtime activities, and morning larks go to sleep earlier even when they engage in these activities right before bed. A normative part of adolescent development is the experience of a ‘phase-delay’, the increasing tendency for many teenagers to feel sleepy later at night and wake up later in the morning when allowed to sleep in. This tendency, or later ‘body clock’, can be attributed to changes in biological processes and rhythms as teenagers mature. So perhaps these bedtime activities are not directly replacing sleep time. Rather, adolescents are engaging in behaviors such as watching television to pass the time in the evenings when they feel alert, until they are ready to fall asleep.

There were, however, some exceptions. Teenagers who frequently played video games right before bed tended to have significantly later bedtimes, regardless of chronotype. This might have to do with the nature of video game playing, such that adolescents might persevere in playing games late into the night, instead of going to bed.

There is also good news: teenagers who spent more time with their families before bed tended to have earlier bedtimes and longer sleep duration. This may be because adolescents who spend more time with their parents have greater parent involvement and input into their nighttime activities, discouraging those problematic behaviors like video-gaming at night.

Furthermore, in the vacation period, engaging in social media activities before bed (such as Facebook, messaging) was related to a significantly longer time taken to fall asleep. This relationship was shown to be related to cognitive arousal (e.g., thoughts, daydreams). Engaging in social media behaviors could increase cognitive arousal, which in turn was associated with more difficulty falling asleep. Interestingly, this relationship did not exist during the school term. Perhaps the sleep restriction that adolescents experience during the week, through later bedtimes but consistently early rise times driven by school schedules, increases their need for sleep at night, so that their sleep drive overrides any cognitively alerting effects of social media.

Importantly, the results from this study suggested that teenagers’ body clock and their day-to-day schedules have much stronger effects on sleep than most bedtime activities. Avoiding certain problematic activities (such as video-gaming) is important, and for adolescents who are prone to sleep onset difficulties, it is also helpful to engage in activities that may lead to feelings of calm and relaxation, such as meditation or listening to relaxing music. In addition, creating a sleep/wake schedule which accommodates adolescents’ particular chronotype (e.g., avoid early morning commitments for night owls), encouraging bright light upon awakening, and being involved in adolescents’ nighttime routines, may be particularly beneficial in assisting teenagers to maximize their sleep and improve their overall well-being.