Sleep Is Not a Luxury: Why Sleep Matters for International Children and Teens

“They sleep enough on the weekends.”

“They’re just a night owl.”

“They can function perfectly well on six hours.”

“They have so much homework — there simply isn’t enough time.”

For many families, sleep becomes something that gets squeezed around everything else: school, homework, sports, friends, screens, activities, family life and travel.

But sleep is not simply downtime. It is an active biological process that supports both the brain and body.

And with schools starting up again after the summer holidays, this is a particularly relevant topic for international families. After weeks of later bedtimes, relaxed mornings, travel and holidays, many children and teenagers are suddenly expected to wake up early, concentrate throughout a full school day and manage homework and extracurricular activities again.

For international families, the transition can be even more noticeable. Summer may have involved travelling across time zones, visiting family abroad or simply adopting a very different daily rhythm. Getting back into a consistent sleep routine can therefore take some time.

As the new school year begins, it is worth remembering that sleep is not something that comes after everything else is done. It is part of what allows children to learn, regulate their emotions, concentrate and function well at school.

Recent research from Columbia University is adding another reason to take sleep seriously: both too little and too much sleep were associated with faster biological ageing across multiple organ systems.

That does not mean that a child who has a few late nights is suddenly “ageing faster.” Nor does the study prove that sleep duration causes faster ageing. But it adds to a much larger body of evidence showing just how deeply sleep is connected to physical and psychological health.

For international children and teenagers, this is particularly worth paying attention to.

The sleep “sweet spot”

Researchers analysed data from around half a million people in the UK Biobank and examined sleep duration in relation to 23 different biological ageing measures covering 17 organ systems.

They found a U-shaped relationship.

People who reported sleeping fewer than six hours, as well as those sleeping more than eight hours, tended to show signs associated with faster biological ageing.

The lowest levels of biological ageing were observed among people sleeping approximately 6.4 to 7.8 hours per day.

But there is an important caveat.

This was an observational study, meaning that the researchers found associations rather than proving that sleep duration itself causes biological ageing. Longer or shorter sleep can also be a marker of underlying health, stress or other factors.

And these findings should not be interpreted as a universal prescription that every person needs exactly seven hours.

Children and teenagers have different sleep requirements from adults, and individual needs vary.

The broader message is much more useful:

Sleep duration and sleep quality matter.

Why sleep matters so much for the developing brain

For children and teenagers, sleep is particularly important because their brains are still developing.

During sleep, the brain is involved in processes that support learning, memory, emotional processing and physical recovery.

This means that sleep isn't simply about feeling less tired the next morning.

A teenager who stays up late studying may feel that they are gaining extra study time. But if insufficient sleep subsequently affects attention, working memory, processing speed, emotional regulation or concentration, that additional hour of studying may not be as beneficial as it seems.

This can create a frustrating cycle:

More schoolwork → less sleep → reduced concentration → more time needed for schoolwork → even less sleep.

Sometimes the answer isn't “work harder.”

It is “protect the conditions that allow the brain to work effectively.”

The international-school sleep challenge

International school life can add some unique complications.

Many international families are balancing demanding academic programmes, extracurricular activities and busy family schedules. Teenagers may also be navigating friendships and social expectations across different cultures and languages.

Then there is travel.

International families may regularly cross time zones to visit relatives, travel for holidays or move between countries. Jet lag and disrupted routines can temporarily shift the body's circadian rhythm — the internal system that helps regulate sleep and wakefulness.

And there is another factor that is particularly relevant for teenagers:

School can start early, while biology may be pushing them towards later sleep and wake times.

This can create a difficult mismatch.

A teenager may genuinely struggle to fall asleep early while still needing to wake up early for school.

So when a parent says:

“My teenager simply refuses to go to bed.”

the situation may be more complicated than simply refusing.

When sleep problems show up as behaviour

One of the most important things parents can remember is that sleep deprivation does not always look like sleepiness.

A tired child may become:

• irritable

• emotional

• impulsive

• forgetful

• unusually active

• easily frustrated

• less flexible

• more sensitive to noise or other sensory input

• less able to manage everyday demands

In teenagers, insufficient sleep can sometimes look like disengagement, lack of motivation or simply “being difficult.”

And this is where sleep becomes particularly relevant when we think about behaviour.

Imagine a teenager who comes home from school and becomes argumentative over something seemingly minor.

The instinct might be:

“Why are you making such a big deal out of this?”

But another question might be:

“How much capacity does this teenager actually have left today?”

Sleep does not explain every behaviour. But it can significantly influence the resources available for managing emotions, attention and everyday demands.

The weekend catch-up problem

One pattern many parents will recognise is the weekday/weekend cycle:

Monday–Friday: too little sleep

Saturday–Sunday: sleeping very late

Sunday night: unable to fall asleep

Monday morning: exhausted

Sleeping longer at the weekend can certainly help with accumulated sleep loss, but large shifts in sleep timing can also make it harder to return to the weekday schedule.

Rather than focusing only on how many hours a teenager sleeps, it can therefore be helpful to consider the bigger picture:

When do they sleep?

When do they wake?

How consistent is the routine?

How rested do they actually seem?

More sleep isn't automatically better either

It is also important not to turn this research into another parental checklist.

More sleep is not necessarily better.

If a child or teenager regularly sleeps for very long periods and still feels exhausted, it may be worth asking why.

Long sleep can sometimes occur alongside other factors affecting wellbeing, including disrupted sleep, physical health difficulties, mood difficulties or an irregular sleep schedule.

The question therefore isn't simply:

“Is my child sleeping enough?”

It is also:

“What does their sleep look like, and how are they functioning during the day?”

Five things international families can do

You don't need to create a perfect sleep routine overnight. Small changes can make a meaningful difference.

1. Protect sleep like you protect school

Homework and extracurricular activities are important. But sleep is not what should be sacrificed whenever the schedule becomes too full.

If a child is consistently working until midnight to complete schoolwork, it may be time to look at the workload and the routine rather than simply expecting the child to become more efficient.

2. Look at the whole week

Don't focus only on bedtime.

Consider school start times, commuting, homework, sports, social activities, screen use, family routines and weekend schedules.

Sometimes the problem isn't bedtime itself.

The schedule is simply too full.

3. Watch for the “tired but wired” child

Some children become more active, silly, emotional or oppositional when they are exhausted.

Don't assume that high energy means they aren't tired.

4. Be realistic about teenagers

Teenagers need increasing independence, and their sleep patterns naturally change during adolescence.

A rigid “lights out at 9:00” approach may become a battle.

Collaborating with teenagers on a realistic routine is often more effective than simply imposing one.

5. Pay attention to patterns

One late night isn't a problem.

Look for persistent patterns.

If a child regularly struggles to fall asleep, wakes frequently, sleeps excessively, is consistently exhausted during the day or experiences significant changes in mood or functioning, it is worth discussing this with an appropriate healthcare professional.

Sleep is part of the bigger picture

Perhaps the most useful takeaway from this research isn't the specific number of hours identified by the researchers.

It is the reminder that sleep is deeply connected to the rest of the body.

The brain does not operate independently from the body. Learning, mood, attention, physical health and emotional regulation are interconnected.

For children growing up internationally, where school demands, transitions, travel and adaptation can already place additional demands on the developing brain, protecting sleep can be one of the simplest ways parents can support their child's overall wellbeing.

As the school year gets underway, rather than focusing only on grades, homework and getting back into the routine, it may also be worth asking:

Is my child getting the sleep they need to actually make the most of all those other things?

Because sometimes the most productive thing a child can do tonight… is sleep.

This article was inspired by research from Columbia University Irving Medical Center published in Nature in August 2026. The study examined associations between self-reported sleep duration and biological ageing measures across multiple organ systems. The findings are observational and do not establish that sleep duration itself causes faster or slower ageing.