Many parents and teachers may hold the belief that teens can be somewhat lazy. Teens seem to sleep in all the time on weekends, may act tired all the time, and it’s often a hassle to get them out of bed for school on time. The common culprit that people run to for an explanation that teens are mismanaging their time and not sleeping at the right time.

But this explanation may not necessarily be true.

There are many biological, social, and behavioral changes that happen during adolescence that may better the reason why sleep seems so much more problematic in this part of human development. These changes make adolescents susceptible to a variety of different sleep problems, such as sleep deprivation, circadian problems, and chronic insomnia.

Consequently, the reason why your teen seems sleepy all the time and it is a monumental task to get them to sleep and wake up at a reasonable hour may not be because of low motivation and poor sleep habits. Below, I discuss each of these factors in turn.

Biological changes push towards a later bedtime

Our circadian rhythm is the internal clock that tells us when we prefer to sleep and wake (along with a host of other processes). People can be ‘early birds’ or ‘night owls’ – and anywhere in between. Our circadian rhythm matures over our life beginning with adolescence.

During adolescence, the circadian rhythm sees a natural push towards a more evening preference (Giannotti et al., 2002). That is, their body biological prefers to sleep a little later compared to when they were children – a 10:00pm to 7:00am sleeper may become a 12:00pm to 9:00am sleeper. During our adult and older adulthood years, we begin to shift towards a more morning preference.

Moreover, there is also research to suggest that the build-up of sleep drive is slower as we move into adolescents but sleep needs stay the same (Carskadon, 2011; Jenni et al., 2005). This process also makes teen stay up longer before they get sleepy because of the reduction in sleep drive, but they still require the same 8 to 10 hours as recommended by the American Academy of Sleep Medicine (Paruthi et al., 2016).

As we can see, the circadian rhythm system and sleep drive system both push adolescents towards a naturally later bed and rise time.

Model of how sleep problems can occur because of changes in teen sleep

Behavioural changes that push towards a later bedtime

Besides biological changes in sleep, there are also changes in sleep habits and behaviours during adolescence that may lead to delayed/poorer sleep.

There may be a social pressure to stay up later; for example, other teens may stay up later to spend more time with each other in the evenings.

Screen time use is also increased during this period (Leatherdale & Ahmed, 2011). There is some research that screen time (e.g., use of phones, computers) can lead to greater levels of alertness and affect production of melatonin (Fossum et al., 2014). However, not all studies have found this relationship (e.g., Wood et al., 2013).

In addition to screen use, adolescents may also be less informed about how sleep habits can affect their nighttime sleep. Adolescents may consume more caffeine in the evening (Martyn et al., 2018), which can affect how long it takes to fall asleep.

School start times conflict with adolescent sleep times

The psychosocial changes in adolescent sleep development conspires with early school start times to cause sleep problems. School start times are typically around 8:00am but teens usually don’t prefer to wake up until a little later because of the evening tendency.

The result is a type of chronic sleep deprivation because of this mismatch between school start times and adolescent sleep preference. It may also be the reason why so many teens ‘catch-up’ on sleep during the weekend by sleeping in.

Unsurprisingly, studies have shown that delaying school start times can have a beneficial impact on sleep health and academic performance in teens (Thacher & Onyper, 2016).

Back to school clock


In conclusion, your teen may not be as lazy as you think. There are biological, social, and behavioural factors that all conspire together to create a ‘perfect storm’ of poor sleep.

Keeping to a consistent bed and wake up routine and reducing nighttime habits that may disrupt sleep can be good ways to support sleep health during the adolescent period. Keeping active during the day can also help to increase sleep drive, leading to deeper sleep. That being said, societal changes, such as changing school start times, could have an important impact on improving sleep health from a systemic perspective.

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Best wishes,