Why Teens Naturally Stay Up Later: And Why They Still Need More Sleep

Let’s talk teenage sleep. We all know babies need plenty of sleep. But there’s another age group where sleep deprivation is just as real, and just as impactful, yet it’s talked about far less: adolescents. That age between 13 and 19.

In this blog we’re going to look at why teenagers naturally stay up later, and why they still need more sleep than they often receive.

The teen years can resemble toddlerhood

Now before you roll your eyes, with that “get a grip” Kim look, hear me out.

The teen years are another critical period for development. Like toddlerhood, most teenagers (like most toddlers) experience the need for more autonomy.  There is rapid physical growth (and often the need for way more food for fuel), and they start firming up their social identity. Their brains are also going through a crucial transformation as they experience all this and continue to build the skills needed for better emotional regulation.

Yes, they’re still growing and learning, even as they’re finishing up high school. But there is a difference in their sleep physiology that we don’t see during toddlerhood (or with primary school children).

The “phase shift” in teen sleep biology

As children enter puberty, their internal body clock, often called their circadian rhythm, changes.

This isn’t just a teen preference, it’s biology.

During the teen years, melatonin, the hormone that tells the brain it’s time to sleep, is released later at night than it is in younger children or adults. This means that our teens really don’t feel sleepy until later, even if an early school starts demand they wake early.

At the same time, their sleep drive, the pressure to sleep that builds throughout the day (the backpack of bricks), accumulates more slowly, so they don’t feel tired at the same time as adults or younger kids. This natural phase shift can last into their early 20s.

And it’s this biological shift that can make most teens seem wide awake late at night, even if they’re exhausted. And why the enforcement of an early bedtime can feel like a battle (they’re really battling their physiology AND likely battling you by striving for more autonomy).

Let’s look at how much sleep teens really need, vs how much they get.

How much sleep teens really need vs how much they get

Most sleep research agrees that teenagers need around 8–10 hours of sleep each night. This is to support brain development, emotional regulation, memory consolidation, and physical growth.  Some teens may even need more than this if they’re into top level sports or still studying at a high level.

But here’s the problem: many teens are getting far less than that.

Studies show that:

• A majority of adolescents do not meet the recommended sleep duration, particularly on school nights.
• Objective measurements (in the States) also indicate teens sleep less than 7 hours on average on school nights.

This gap between sleep need and actual sleep received creates a chronic sleep deficit, sometimes called sleep debt. Then when teens try to make up sleep on weekends (because the later drive to sleep, also means a later time to wake the next morning), it can throw off their rhythm even more by disrupting their body clock.

Why is missing sleep a big deal?

Why this matters: the science behind sleep & brain development

Sleep is not just “rest.” It’s a critical physiological process that supports:

• Brain development and neural connectivity: especially in areas responsible for decision-making, memory and emotional regulation.
• Glymphatic system clearance: the brain’s way of clearing waste and toxins that accumulate during waking hours.
• Emotional balance and resilience: insufficient sleep is linked with higher risk of anxiety, depression, mood swings, and impulsivity.

Even modest increases in sleep have measurable effects. In large adolescent studies, those with better sleep timing and duration showed better cognitive performance and brain health markers compared with their peers who slept less.

But modern expectations have squeezed sleep into a shorter window.

The mismatch between biology and expectations

A teenager’s biological tendency to stay up later clashes with:

• Early school start times
• Early morning sports practices
• Homework and extracurricular loads
• Evening screen time
• Social and mental demands

This combination pushes bedtime later and wake-up times earlier, squeezing sleep duration shorter and shorter.

Research also shows that earlier school start times are strongly associated with shorter sleep durations. When really, the teen years are when school should be starting LATER (not earlier).

 By simply delaying school start time (or even moving sports practices later), the extra lie in can increase total sleep by about 40+ minutes per night. And this can also improve school performance.

But it can get trickier.

As well as the earlier school times not gelling with the delayed sleep phase shift, there is the common problem of your own teen not listening to you. Don’t panic over that, it’s their brains craving more autonomy as they are getting ready to fly the nest.

But there are solutions.

How we can help teens get more (and better) sleep

Let’s be honest, teens often ignore parental requests about bedtime. But there are science-informed strategies that can help:

1. Educate them about the sleep phase shift

Understanding that it’s not “laziness” but a normal biological shift can help teens take ownership of their sleep. Some teens respond well when they see the science behind it.

2. Start with small, positive changes

• Encourage consistent sleep–wake times, even on weekends.
• Cut evening screen time at least 1 hour before bed (yes, that means having conversations about their phone).
• Bright light exposure in the morning helps reset their circadian clock.

3. Model healthy sleep routines

Teens are more likely to respect routines when they see them practised at home and when the focus is on feeling better, not “because I said so.” How is YOUR sleep going?

4. Advocate for structural changes

If possible, support conversations with schools and sports teams about later start times. This is a strategy that has shown to extend sleep and improve daytime functioning.

5. Focus on outcomes, not orders

Talk to teens about what better sleep looks like for them:

• Better mood
• Improved memory and focus
• More energy for sport/friends
• Less grogginess in mornings

Teens may actually choose sleep when they understand what it helps them do, rather than what it prevents them from doing.

This article was originally published by Cherished Sleep here