Why your teenager cannot sleep before midnight, and what still works

It is half past eleven and they are still awake. The alarm is set for seven, the school run is at eight, and the same argument is happening on the landing that happened last night.

Before you have it a third time, it is worth knowing what you are arguing with. It is not attitude. It is a clock, and the clock has moved.

The body clock really does shift in puberty

Sleep clinics in the NHS describe it plainly: during adolescence the brain starts releasing melatonin, the hormone that makes you feel sleepy, later in the evening than it did in childhood. The whole schedule slides later by about two hours. A child who was drowsy at nine becomes a teenager whose natural falling asleep time sits somewhere between eleven and midnight.

Nothing has gone wrong. It happens to most teenagers and it is a stage of growing up, not a permanent setting. But while it lasts, telling a fourteen year old to be asleep by half nine is like telling someone who has just flown in from New York to be asleep at teatime. Their body is running on a different time zone from the rest of the house.

Why the school day makes it worse

The trouble is that school does not move. If they cannot drop off until half eleven and the alarm goes at seven, that is a short night, repeated five times. Teenagers need roughly eight to ten hours. On that timetable they are not getting it.

Then Saturday arrives and they sleep until one in the afternoon. It feels like catching up. What it actually does is push the clock later still, so Sunday night is the worst night of the week and Monday morning the worst morning. The lie-in resets the problem.

Stop fighting bedtime. Move it.

This is the part that feels wrong. If your teenager is lying awake for an hour every night, the bedtime is too early for their clock. Sending them up at nine and expecting sleep teaches one thing only: that bed is where you lie in the dark feeling cross.

NHS sleep services suggest the opposite of what instinct says. Set bedtime later, to a time when they genuinely fall asleep within twenty minutes or so. Half ten is a reasonable place to start. Once they are dropping off quickly and reliably, bring it forward by fifteen minutes every few days. How easily they fall asleep matters more than the number on the clock.

Morning is where the work happens

Everything that actually moves a body clock happens in the morning, not at bedtime.

Hold the wake time steady, seven days a week. This is the hardest thing on the list. It is also the one that works. Weekend lie-ins can stay, but put a ceiling on them: up by nine or ten, not noon. An extra hour is a treat. An extra five hours is jet lag.

Get daylight into them in the first twenty minutes of being up. Not a bright bathroom bulb. Actual daylight, through a window with the curtains fully open, or better, outside. A grey September morning in Britain still does the job, and it does it far better than any indoor light. If they walk to school, that walk is doing more for their sleep than anything you could buy.

The evening still matters, just less than you think

Dim the lights in the last hour. Melatonin does its job better in low light, and a bright kitchen at ten at night is telling their brain it is still afternoon.

Phones out of the bedroom, or at least off, an hour before bed. You will not win this one by decree. It works better as a house rule that applies to everyone, including you.

Watch the caffeine after lunch. Energy drinks and cola are the obvious ones, but tea, green tea and chocolate all count. Caffeine hangs around for hours and nudges the clock later.

If they are lying awake

If sleep has not come within twenty or thirty minutes, staying in bed makes it worse. Have them get up, go somewhere dim, read or listen to something quiet for a quarter of an hour, then try again. It feels backwards, but it stops the bed becoming the place where sleep does not happen.

Tonight

Do not touch bedtime tonight. Instead, agree two numbers with your teenager: the wake time for the week, and the latest they will be up on Saturday and Sunday. Write both on the kitchen calendar. Then open their curtains in the morning before you do anything else.

Give it a fortnight before you judge whether it is working.