Regular bedtimes better for young minds
July 8th, 2013
06:35 PM ET

Regular bedtimes better for young minds

If your children are throwing temper tantrums because sleep seems unappealing, consider that it may be OK to let them stay up a little longer, as long as bedtime happens around the same time every night.

A new study suggests that consistency of young children's bedtime is associated with positive performance on a variety of intellectual tests. The study was published in the Journal of Epidemiology and Community Health.

"If the child prefers to go to sleep a little bit later, but it’s done regularly, that’s still OK for them, according to the evidence," said Amanda Sacker, professor in the Department of Epidemiology and Public Health at University College London.

The study

Researchers looked at information about bedtimes and standardized test scores for more than 11,000 children who were part of the UK Millennium Cohort Study, a nationally representative study of children in the United Kingdom.

The Millennium Cohort Study followed children when they were aged 3, 5 and 7, and included regular surveys and home visits. Researchers asked parents about family routines such as bedtimes.

Children also took standardized tests in math, reading and spatial abilities when they were 7 years old.

Researchers controlled for socioeconomic status in addition to other factors such as discipline strategies, reading to children and breakfast routines.

The results

The study found that, in general, consistent bedtimes were linked to better performance across all subject areas. This was especially true for 7-year-old girls, regardless of socioeconomic background - they tended to do worse on all three intellect measurements if they had irregular bedtimes. Boys in this age group did not show the effect.

In both girls and boys, non-regular bedtimes at age 3 were linked with lower test scores, but not at age 5.

Bedtimes that had never been consistent for girls at ages 3, 5, and 7 were associated with lower scores than regular bedtimes. For any two of these ages, boys also tended to do worse on the tests if they didn't go to sleep at a routine time.

These results "showed that it wasn’t going to bed late that was affecting child’s development, it was the irregular bedtimes that were linked to poorer developmental scores," Sacker said.

Why did girls appear to be more strongly affected by irregular bedtimes than boys? "It might be that girls are more susceptible to elements of the psychosocial environment than boys, and hence also more easily perturbed by inconsistent bedtime schedules," the study authors wrote.

Sacker and colleagues had initially suspected that late bedtimes would also be associated with poor cognitive test performance, but this turned out to not matter, when other factors such as socioeconomic status were controlled for.

Researchers found that, in general, children who had irregular bedtimes or went to bed after 9 p.m. tended to come from lower socioeconomic backgrounds than other study participants. These were the children more likely to be from poor homes and have mothers with poorer mental health. They were also less likely to have breakfast and be read to daily.


The study used a large group of participants but still only draws correlations, not causes. It is not proof that irregular sleep is a direct driver of lower test scores.

Also, information about bedtimes came from parents' self-reporting, and were not independently verified.

Researchers also did not assess the length of sleep that the children typically had. Parents reported on what time their children went to bed or whether there was no regular bedtime, but did not state exactly how much sleep they received.

The answers to the questions of exactly what represents a "regular" bedtime - is it OK to vary lights-out by an hour? A half an hour? - are still unknown.


There are a few possible explanations for the observations in the study. One is that children with an irregular bedtime may not be getting good quality sleep. Also, the body's circadian rhythms can be disrupted when a person doesn't have consistent sleep schedules.

Each day, as environmental stimuli influence changes in the brain, we need sleep to allow fresh learning for the day to come, according to the study. Cognitive impairment and lack of concentration are two possible consequences of limited or disrupted sleep. Given the importance of childhood development, study authors say, low-quality sleep in this critical period could have long-term health effects.

The study supports other research showing that adults also benefit from having consistent bedtimes.

"It not only helps with what’s gone on the day before, but it also sets you in good stead for the day to come," Sacker said.

That makes it worth finding a consistent time to tuck in the little ones - and yourself.

More on CNN Health: How poverty might change the brain

Follow Elizabeth Landau on Twitter.

soundoff (40 Responses)
  1. Dan

    Mom was right. Don't tell her.

    July 8, 2013 at 19:57 | Report abuse | Reply
    • Nahzuul

      Ah, it's okay to tell her now. Pretty soon I'll be telling her when to go to bed. Now I have a study to back me up that she never had . . . mwahahahahaha!

      July 9, 2013 at 00:29 | Report abuse |
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      July 10, 2013 at 21:45 | Report abuse |
  2. Tom

    So that means daylight savings time is bad for kids. Maybe that can make it go away forever (or stay year round – I don't care which, just pick one).

    July 8, 2013 at 21:02 | Report abuse | Reply
    • Ricardo

      No, it doesn't mean that at all because the cycle of events that a child goes through remains the same with only a minor adjustment at the DST time changes.

      July 8, 2013 at 21:17 | Report abuse |
  3. Amy

    Tom, I don't know where you live, but around the solstice, the sun rises at 5:30 a.m. – if we didn't have DST, it'd be 4:30 a.m. I don't want the sunlight hitting my eyes that early. And yeah, I can close the blinds, but why sleep through 2 hours of daylight when I don't have to get up until 6:30 a.m.? I'd prefer the extra hour of daylight when I come home from work and can mow my lawn, swim in my pool, ride my bike, grill my dinner. What's your problem with DST?

    July 8, 2013 at 21:22 | Report abuse | Reply
    • Blob

      That's why we should be on DST all year round

      July 8, 2013 at 21:35 | Report abuse |
  4. Leanne Palmer

    Excuse me, but I am a single mother, I work late. I support my children, they see their father. We read to them, and guess what I feed them breakfast, lunch, and EVEN supper. WOW. That's more than I can say for some married couples that raise kids together. Start a new study to make people feel down on themselves. How about, people who do studies have nothing better to do.

    July 8, 2013 at 21:23 | Report abuse | Reply
    • TJ

      Ah – read the article again – it really does not have anything to do with single parenting. Just whether kids do or do not have regular bed times. Maybe you should consider that – it might help with your comprehension.

      July 8, 2013 at 23:26 | Report abuse |
    • ThatRandomGirl

      I applaud you for being a single mother, but I think this is just saying how regular sleep times are useful. You can try to imploy them best you can.

      July 9, 2013 at 10:52 | Report abuse |
    • Roklobster

      Did you even read the article or just bristle and puff and talk about being a single mom because you saw an article with "kids" in it?

      July 9, 2013 at 14:16 | Report abuse |
    • BRB

      You are not a single mother – you are a divorced mother BIG DIFFERENCE.

      July 9, 2013 at 19:42 | Report abuse |
  5. Mark

    What a shock, consistency is good for kids. Color me unimpressed with this study.

    July 8, 2013 at 21:49 | Report abuse | Reply
  6. PHinMiami

    To all those parents dragging their cranky kids to Walmart at 11 pm, "Shame on you!". This article accurately describes the 'type' of parents that do it.

    July 8, 2013 at 21:51 | Report abuse | Reply
  7. jack brown

    This is an example of how to do science writing well. My first reaction on reading the headline and the first two paragraphs was, 'well, parents who put their kids to bed consistently are just better organized parents in general, doesn't mean the bedtime is causative.'

    But the writer answers this question, "Researchers controlled for socioeconomic status in addition to other factors such as discipline strategies, reading to children and breakfast routines." So, maybe there IS something to regular bedtimes....

    Thanks for addressing the question in your write-up.

    July 8, 2013 at 22:20 | Report abuse | Reply
    • elandauCNN

      You're welcome! Thanks for the compliment and for reading!

      Elizabeth Landau, CNN

      July 8, 2013 at 22:34 | Report abuse |
    • DarkAgeWarrior

      I was thinking the same thing. Certainly not conclusive evidence but at least this was presented in a way that gives some clear meaning.

      July 9, 2013 at 02:32 | Report abuse |
  8. TrustKnow1

    Good luck with that! The Powers That Be of the NWO have known about this for years. Coupled with video games, rap music and a host of other subliminal techniques, the average American child is doomed to self destructive behavior that they don't even understand. Think more... Follow less... The truth is out there!

    July 8, 2013 at 22:25 | Report abuse | Reply
  9. singularity2029

    Its a BS study because the parents that have rigid bed times are more likely to be rigid when it comes to studying and school. Its pretty obvious that the parent that lets their kid sleep whenever they want will most likely not be as disciplined when it comes to course work.

    Once again a bogus study that proves nothing scientific

    July 8, 2013 at 22:30 | Report abuse | Reply
    • Nahzuul

      You now what doesn't prove anything scientific? Sheer speculation.

      "Researchers controlled for socioeconomic status in addition to other factors such as discipline strategies, reading to children and breakfast routines."

      Science is just whatever you decide it to be. Learning about science requires good reading comprehension and an open mind.

      July 9, 2013 at 00:42 | Report abuse |
    • Nahzuul


      "now" should be corrected to, "know"

      "Science is just whatever you decide it to be." should be, "Science isn't just whatever you decide it to be."

      July 9, 2013 at 00:48 | Report abuse |
  10. ram

    Kids-at least in the US-have a lot more today to stimulate them than past generations: x box, WI, Cell phones which now supply more than phone service. My wife & I have had our 4 grandkids-12 to 4 yrs-as well as their mom, living w/us the past 5 yrs. I agree w/this study, because kids have more on their shoulders than ever before as well.

    July 8, 2013 at 23:15 | Report abuse | Reply
  11. rumrum

    I don't know whether I agree that irregular bedtimes contribute to poor intellectual performance, I'm leaning towards disagreeing with this study. I will say however that I was a child that had extremely irregular bedtimes. I could sleep whenever I wanted to and get up whenever I wanted to, so long as I went to school everyday. I was very much a straight A student in school, I actually enjoyed going and did well, school was great for me and I think the confidence it helped me develop actually helped me be more of an intellect (not to say that I'm a sanctimonious know-it-all), but sure, I was a smart kid. The biggest problem with irregular bedtimes has nothing to do with intellect but DISCIPLINE! I learned no discipline because of the freedom I had in choosing when I wanted to sleep. I am not a parent but will make sure that any kids I have one day will follow a strict bedtime, because it's damn hard learning and teaching yourself discipline as an adult! Having these little routines really does help in the overall personal development of a child I believe, no matter how little you think they are. Man I wish my parents would have been stricter when I was a kid!

    July 8, 2013 at 23:21 | Report abuse | Reply
  12. Jeff

    What would have made this more valuable to parents would be if the variance on beditmes was included. Is this a consistent bedtime within a 15-minute window? 30-minutes? 1 hour? I'd like to believe I'm consistent with bedtime, but how are the researchers defining consistency?

    July 8, 2013 at 23:21 | Report abuse | Reply
  13. Dave

    Maybe children with regular bedtimes live in more structured and supportive environments leading to higher test scores while irregular bedtimes may suggest a lack of stability. Is it the sleep or the environment? Or is it all a bunch of malarkey?

    July 9, 2013 at 01:19 | Report abuse | Reply
    • Mark

      yep..agree with you presumption...

      October 18, 2013 at 13:11 | Report abuse |
  14. MyNameIsJoseJimenez

    Another non-scientific study which isn't worth the bits it is comprised of.

    July 9, 2013 at 02:15 | Report abuse | Reply
  15. Chilly8

    The thing is that a resourceful youngster will find a way to get TV after bed. When I was a youngster, I would merely turn on the TV in my bedroom, but turn down the sound and picture, and then listen to the audio through a police band receiver I had, tuned to about 38Mhz, and my parents were never the wiser. Just stick an earplug in an ear and listen.

    In short, children will become resentful about early bedtimes. I know I was.

    July 9, 2013 at 07:38 | Report abuse | Reply
  16. lena

    This is why you are not supposed to have a TV in your bedroom. Though I agree about kids being resourceful: I used to try reading by the moonlight.

    July 9, 2013 at 08:06 | Report abuse | Reply
    • Leblanc82

      I used to try to read after bedtime also. I had a strict bedtime. I tested well throughout school even though I have a severe learning disability. A routine helped me throughout school and even as an adult.

      July 18, 2013 at 18:31 | Report abuse |
  17. Jim

    This one goes in the NSS (No Sh** Sherlock) file.

    July 9, 2013 at 09:28 | Report abuse | Reply
  18. Troy

    This is news? Money was spent to study this? Any parent that doesn't inherently know that regular bedtimes are better for kids should be sterilized. Morons.

    July 9, 2013 at 11:05 | Report abuse | Reply
  19. BRB

    Sanjay is a effin genius. Why didn't someone else think of this? How can we miss you if you won't go away.

    July 9, 2013 at 19:37 | Report abuse | Reply
  20. Zephyrous

    A genuinely well-written and complete article that flows well with not a single glaring grammatical, contextual or spelling error. Such an absolute rarity at CNN. Can this author please write or edit ALL articles on CNN from now on? Please?

    July 10, 2013 at 00:06 | Report abuse | Reply
    • ahayesCNN

      Thank you Zephyrous. Elizabeth is one of our staff writers and writes for us often. Ashley Hayes, CNN

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  22. Jojo

    A. get rid of the freaking spam here please.

    B. When I was in elementary school, tu ended after the news, society frowned on the bar scene, and most people had jobs. I dunno. Could an earlier, more stable bedtime be at ALL related to that?? lol!

    July 14, 2013 at 16:18 | Report abuse | Reply
  23. Bill

    Wish I could find a way to simply email this article to somebody(?)

    July 15, 2013 at 09:54 | Report abuse | Reply
  24. markwfcondon

    If you want to boost the intellectual impact of regular bedtimes, just add a lead-in reading time to the routine. The resulting boost in language that happens through loving conversation around those books is a joy-filled plus.
    No books? If you have a smartphone (tablet or laptop(), just go to http://UniteforLiteracy.com and there you will find not only 100 cute picture books for new readers, but they come with on-demand narration in up to 15 different languages.

    August 15, 2013 at 12:32 | Report abuse | Reply
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