Active kids sleep better

A paper in Archives of Disease in Children documents a New Zealand experiment in which children's sleep habits were tracked against their activity, as measured by an actigraph. The conclusion won't surprise many parents: kids who run around all day sleep more at night (and kids who sleep more at night are more apt to run around all day).
The study included 519 healthy 7-year-olds from New Zealand, who each wore a device called an actigraph for 24 hours. An actigraph records movement, providing an objective measure of a child's activity level and sleep time. Parents also noted when their child went to bed, which allowed researchers to calculate how long after bedtime children actually fell asleep.

The researchers found a wide variation in how quickly children fell asleep, with some taking as little as 13 minutes and others needing more than 40 minutes after going to bed. Within this range, there was a close relationship between the onset of sleep and daytime activity. On average, children took an extra three minutes to fall asleep for every hour they weren't moving about. Also, the children who fell asleep faster slept longer overall. On average, children got one extra hour of slumber for every 11-minute drop in how long they took to get to sleep.

Active days mean better bedtimes (via Consumerist)


  1. Maybe kids who sleep enough are more energetic and active in general? Did they measure against the nights after more or less activity from one kid?

  2. Then they removed the devices and the more active children were taken to battle school…

  3. I think this is one of those truths that every parent (?) knows… if you wear your kid out at the park after school, they’ll be both better behaved and happier in general, and sleep through the night without problem. On one hand I’m happy to see a study confirming that, but on the other hand… duh!

  4. I agree with this article, but more importantly, I must know: where can I get one of those red stuffed robots? I’d like one for my son.

  5. … and in other news scientists recently revealed a study which shows that water is wet, and fire is hot. Hmm, who’d of thunk it?

    Off to you Sandy, I hear there’s a story about a box of kittens?

  6. have to agree with #2… you wear the kid out so they sleep better and their mental state is much better overall.

  7. @3, exactly! When I ran around all day I sleep better too. And people get paid to research this?

  8. I teach Judo to kids, and I try to make the practices hard but fun, for just this reason. Tired children make for happy parents.

  9. Why is the picture of an infant if the test was with seven year olds? Seems to me someone needs to get a little more sleep before picking their art!

  10. @All those saying ‘duh’: yes, it’s one of those things ‘everyone knows’. Everyone knows that things fall towards the ground, too, but do they know that the gravitational force between two masses is proportional to their product and inversely proportional to the square of their separation? Quantifying these things sometimes tells us new things.

    @11: Not anymore, I think. When I was a baby, apparently the advice was on-stomach. As an adult, I can’t sleep in any other position. I’d be interested to know if one is patterned when young.

  11. Oh, great! Now maybe they could pay some people to conduct a study regarding the immediate effects of rain on pavement.

    “After months of vigorous testing, we are pleased to announce our results. Ahem. Wet.”

    We’ll need more scientists of course. Job creation, no? I wonder where I can find an application to attend the New Zealand School of No-Brainers.

  12. Wow, I would think this study would be a siren song for all scientists who have been having trouble getting their projects funded to go to New Zealand. The grant committees there are apparently fairly lax.

  13. #12:

    I think you’re not supposed to let your baby sleep on his/her stomach.

    Try stopping the little buggers, though. For that matter, if the consensus on the matter changes, and you are supposed to lay ’em on their fronts, good luck getting them to sleep that way too…

  14. While active children sleep better (and i’ll add my ‘duh’ to the chorus) it’s not a good idea to have them running around right before bed time. Kids need time to get into ‘sleeping mode’.
    I’d be interested to see if the effect reverses at a certain level of activity. In my experience, kids who are completely exhausted don’t sleep very well.
    It’s pretty widely known that enough sleep is extremely important for children and adolescents. I know of several campaigns to discourage parents to allow TVs, computers, game consoles and even comics in their kids’ bedrooms. Just so they don’t spend half the night reading/gaming.
    All this probably goes for adults to, if only we all had our eight ours of sleep every night, the world would undoubtedly be a wonderful place.

  15. I think you’re not supposed to let your baby sleep on his/her stomach.

    That may be true for your baby, Cory’s baby requires a better citation (please) before accepting such unsought advice.

  16. Geez, you’d think from some of these comments that I’m reading the local newspaper website. Science is important guys, and a lot of things we think are true aren’t always correct, hence why we actually need to test things to see what’s happening!

    And for those who think there is lots of funding in New Zealand, you’re wrong. I live in New Zealand and am a researcher so I know what I am talking about.

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