A teenager who gets enough sleep remembers lessons better, stays focused longer in class and handles emotions better. Yet adolescence is exactly when sleep goes off track. Here is how many hours of sleep are needed at each age, why your teenager goes to bed later and later, and how to help without conflict.
How many hours of sleep does a teenager need?
In 2016, the American Academy of Sleep Medicine (AASM) published age-based recommendations, based on an expert consensus and endorsed by the American Academy of Pediatrics. They are used as a reference in many countries:
- 6 to 12 years: 9 to 12 hours of sleep per 24 hours;
- 13 to 18 years: 8 to 10 hours per 24 hours;
- from 18 years: at least 7 hours a night, according to the AASM and the Sleep Research Society.
In practice, a teenager aged 12, 13 or 15 needs 8 to 10 hours, and so does a 16 or 17 year old. These are ranges: some feel fine with 8 hours, others need nine and a half. The best guide remains how your child feels during the day.
What time should a teenager go to bed?
Start from wake-up time. A pupil who gets up at 6:30 am to catch the bus should be asleep between 8:30 pm and 10:30 pm to get 8 to 10 hours. Add the time it takes them to fall asleep.
In practice, a realistic goal for a secondary school pupil is often lights out around 10 pm on school nights, with a steady wake-up time.
Why sleep matters so much for success at school
At night, the brain does not switch off. It sorts through what was experienced and learned during the day, and consolidates part of it into long-term memory. Deep sleep, more abundant early in the night, plays an important role in this consolidation.
According to the AASM, getting the recommended amount of sleep is associated with:
- better attention and concentration;
- better learning and memory;
- steadier behaviour and emotional regulation;
- better mental and physical health.
Sleep is no substitute for work, of course. But a tired pupil gets much less out of the hours spent in class or on schoolwork.
Signs that your teenager is not getting enough sleep
Lack of sleep does not always show up as yawning. Look out for:
- great difficulty waking up and repeated lateness in the morning;
- irritability and mood swings;
- trouble concentrating, forgetfulness, homework left undone;
- falling grades with no clear explanation;
- very long lie-ins at the weekend, a sign of “sleep debt” built up during the week.
In the longer term, the AASM points out that insufficient sleep increases the risk of accidents, obesity and depression, among other things.
Is your child falling asleep in class?
A pupil who falls asleep in class is not necessarily lazy or uninterested. Most often it is a sign of short or poor-quality sleep. Talk to them about it, and to their form teacher if it keeps happening.
If sleepiness persists despite enough sleep, or if your teenager snores loudly, see your GP: some sleep disorders can be treated.
Why teenagers go to bed later and later
It is not just a matter of unwillingness. At puberty, the body clock shifts: melatonin, the hormone that prepares the body for sleep, is released later in the evening. Many teenagers genuinely do not feel sleepy at 9 pm.
The problem is that school hours do not shift with it. In the evening, other factors push bedtime back even further:
- screens, whose light and above all content (messages, videos, games) keep the brain alert;
- homework started late;
- evening extracurricular activities;
- stress, especially before exams.
On the place of phones and social media in young people’s lives, see also our article on the impact of social media on young people and students.
How to help your teenager sleep better
Rules imposed on their own rarely work with a teenager. Explain why sleep helps them succeed, then agree together on a few simple habits:
- regular hours, weekends included, without shifting wake-up time too much;
- daylight in the morning, which helps reset the body clock;
- screens out of the bedroom at night, with a shared charging spot for the whole family;
- a dark, quiet and cool bedroom;
- no caffeine or energy drinks late in the day;
- sport or physical activity during the day, rather than just before bed;
- a short nap in the early afternoon if needed, but not late in the day.
Lead by example: a teenager follows a rule more easily when their parents follow it too.
When is the best time to learn lessons?
Sleep helps consolidate what was learned in the hours before. An effective method is therefore to go over lessons quietly in the evening, then review them briefly the next morning.
Be careful, though, not to study at the expense of sleep. Studying late and cutting back on sleep often costs more than it gains. To organise work over the week, our 5 tips for studying and passing your exams can help.
The night before an exam
The night before an exam is not the time to go over everything. A full night’s sleep makes you more alert and helps you recall what you have learned. It is better to plan revision so that it ends at a reasonable time.
This also applies to students in higher education during the study period before exams (the “blocus”): the temptation to cut nights short is strong, yet concentration depends directly on sleep.
When tiredness hides difficulties at school
A teenager who goes to bed late because homework never seems to end may above all have a problem with organisation or understanding. Homework takes longer, nights get shorter, and difficulties pile up.
Support can break this cycle. At My Sherpa, an educational advisor chooses a coach suited to your child’s needs, for private tutoring in secondary school or work on study skills. Lessons take place at home, anywhere in Belgium, or online.
