We cut screen time for two weeks. Here's what happened to the children.

It's half past four. Homework is done, and your nine-year-old has been on the iPad since you got home. You're thinking about saying something. But you've also heard that screen time might not be as bad as people make out. So is it even worth the argument?

Danish researchers have actually tested that question. Not by asking parents what they think, but by getting real families to cut back and measuring what happened. Here is what they found — and what it means at your house.

The trial: 89 Danish families cut back for two weeks

Researchers at the University of Southern Denmark invited families with school-age children from ten municipalities in the south of Denmark. All of them used a fair amount of screen time in their leisure hours — more than average. 89 families with 181 children said yes.

The families were split by lottery. One half had to keep leisure screen time to at most three hours a week for two weeks — for the whole family, parents included. The other half carried on as usual. Every child wore a small activity monitor around the clock, so the researchers could see what the children actually did instead of asking afterwards.

The lottery matters. It means the difference between the two groups comes from the screens — not from some families simply being more active or more organised than others.

What happened: 45 minutes more activity a day

Children in the families with less screen time were on average 45 minutes more active every day than children in the other families. Not because they were sent to football practice. The time simply came by itself: when the screen wasn't there, the children found something else to do, and that something was more often on their feet.

The researchers also measured the children's wellbeing with a questionnaire used by school psychologists around the world. Here too the children did better after two weeks: fewer worries and low moods, fewer problems with friends, and more helpfulness towards others.

A couple of things belong here. The trial lasted only two weeks, and the families were ones that used a lot of screen time to begin with. The children's sleep did not measurably change. And whether the effect lasts once a family has lived with less screen time for six months is not yet known. But two weeks was enough to see a difference you can feel.

The eyes: every hour counts

More and more children are becoming short-sighted, and here the research is unusually clear. In 2025 researchers pooled the results of 45 studies covering more than 335,000 children and young people. The pattern was the same across them: for every extra hour a day in front of a screen, the odds of short-sightedness rose by about a fifth. The risk climbed most steeply between one and four hours a day — exactly where most children are.

The good news is that it can be offset. In a trial with six-year-old schoolchildren, one group got an extra 40 minutes outdoors every school day. Three years later, fewer children in that group were short-sighted. Daylight protects the eyes, and it takes nothing more than being outside.

It should be said that the screen-time studies show an association, not proof. But the direction is the same across all 45 studies, and the advice is simple: less time close to a screen, more time in daylight.

The evening: switch off in good time, not when your child lies down

Your body uses light to know what time it is. As evening comes, it starts releasing the sleep hormone melatonin, which makes you drowsy. Light in the eyes says the opposite: it's still daytime.

How much that matters for children was tested by American researchers in 2022. 36 children aged 3–4 were given an hour of light in the hour before their usual bedtime. The sleep hormone fell by 69–99 % — including in children who got only dim light, dimmer than an ordinary living-room lamp. And it did not bounce back quickly: in six out of ten children the hormone was still below half its normal level 50 minutes after the light went off.

The trial was small, it was about young children, and it measured the hormone rather than sleep itself. But it explains why the Danish Health Authority and the Danish health visitors advise no screens for 1–2 hours before bedtime. A screen that goes off at eight, as the child lies down, is too late. We've written more about evenings in how to turn off Wi-Fi for kids at night and my child is online all night.

What does it mean at your house?

There is no single right number of minutes. The Danish Health Authority says itself that the research cannot tell where the line is. Its guideline for 5–17-year-olds is at most 1–2 hours of leisure screen time a day. What the trials above show are three things worth doing something about:

• Cut down in everyday life. The Danish trial shows that less screen time frees up time that children fill with activity by themselves. You don't need to plan what they'll do instead.
• Give the time somewhere to go. Screen-free time after school is time that can be spent outdoors — and that's good for both body and eyes.
• Switch off in good time in the evening. A fixed time when the internet goes off an hour or two before bed is easier than a negotiation every night.

Make the agreement together with your child. When the child knows when and why, it's a house rule rather than a punishment. In the Danish trial, by the way, it was the whole family that cut back — parents too. A rule you follow yourself is easier to keep.

How Owlyfi helps

The hard part isn't agreeing on the rule. The hard part is keeping it at half past eight on the third evening in a row. Owlyfi turns the agreement into something that happens by itself on your home Wi-Fi: you set up a schedule — say, screen-free time after school and a shut-off time in the evening — and you can pause the internet for particular devices when you need to. Nothing is installed on your child's phone, and Owlyfi doesn't read messages, track location or look at browsing history.

Owlyfi doesn't control mobile data, and a pause on the home network doesn't stop games that run without internet. Nor does Owlyfi promise better sleep or healthier eyes. It's the agreement and the habits that make the difference. Owlyfi helps you keep them.

Sources

1. Pedersen et al. (2022), JAMA Pediatrics: Effects of Limiting Recreational Screen Media Use on Physical Activity and Sleep in Families With Children — the Danish SCREENS trial: 89 families, 181 children, 45.8 minutes more activity a day, no difference in sleep.
2. Schmidt-Persson et al. (2024), JAMA Network Open: Screen Media Use and Mental Health of Children and Adolescents — same trial, children's wellbeing measured with the SDQ questionnaire.
3. JAMA Network Open (2025): Digital Screen Time and Myopia: A Systematic Review and Dose-Response Meta-Analysis — 45 studies, 335,524 participants, 21 % higher odds of myopia per extra hour a day.
4. He et al. (2015), JAMA: Effect of Time Spent Outdoors at School on the Development of Myopia Among Children in China — 40 extra minutes outdoors a day, fewer short-sighted children over three years.
5. Hartstein et al. (2022), Journal of Pineal Research: High sensitivity of melatonin suppression response to evening light in preschool-aged children — 36 children aged 3–4, 69–99 % lower sleep hormone after an hour of light before bedtime.
6. Danish Health Authority (Sundhedsstyrelsen): Recommendations on screen use.
7. Danish health visitors (Sundhedsplejen): Screen-time recommendations — no phone, computer etc. 1–2 hours before bedtime.

All sources accessed 30 October 2026.