What time do you go to bed at night? I don’t know your personal schedule. You might be an early riser or a night owl. But chances are, you let your brain chemistry be the guide. When researchers have monitored American adults, they’ve found that people go to sleep approximately two hours after their brains start to make extra melatonin, the hormone of drowsiness.
Two hours. That might mean your body starts feeling a rise in melatonin at 9:00pm, but you aren’t sleepy yet. So you go about your business, try to unwind, and then, finally, as melatonin levels keep increasing, you go to bed at 11pm.
But what about kids? Monique LeBourgeois wanted to know, so she and her colleagues fitted 45 healthy toddlers with wrist actigraphs – little bracelets that provide a continuous record of wakeful and sleep states. The researchers also asked parents to keep sleep diaries, noting when kids went to bed and when they woke up in the morning. And most importantly, LeBourgeois and colleagues devoted a day to collecting melatonin samples from the children. Starting in the afternoon, researchers hung out with families in their homes, taking saliva samples from the children every 30 minutes until one hour past the kids’ normal bedtimes.
The results were eye-opening. The average onset of the evening surge in melatonin, or “dim light melatonin onset” (DLMO), happened around 7:30pm, but kids didn’t go to bed two hours later. Instead, their average bedtime (lights out) was 8:15 pm, and – guess what – they didn’t go right to sleep. According to the actigraphs and sleep diaries, the average time of sleep onset was approximately 30 minutes later.
So the average kid was put to bed with the lights turned out just 45 minutes after his DLMO, and didn’t fall asleep for another half hour. Is this good? I don’t know. Sleep doctors often say that healthy people should be able to fall asleep within 20 minutes of putting their heads down. When it takes longer, we’re at risk for sleep problems: We may come to associate being in bed with feeling alert, and develop a kind of learned insomnia. According to this research, the average kid may be going to bed a bit too early.
And if that’s true, what about all the kids who go to bed earlier than average? Or the kids who have later-than-normal DLMOs? Some of the kids in this study took more than 90 minutes to fall asleep, and they were usually the kids with the earliest bedtimes. In fact, LeBourgeois and colleagues found that 1 in 5 kids were sent to bed before their evening melatonin surge had even begun. Imagine what that would be like – being asked to lie in bed while your brain thinks it’s time to party. No wonder if many kids resist bedtime.
Curious if these mismatched bedtimes were an important cause of sleep trouble, LeBourgeois led a follow-up study. Her team confirmed that kids whose melatonin surged later in the evening took longer to fall asleep after lights out, but it also depended on bedtime. The earlier kids were put to bed relative to their DLMOs, the longer it took them to sleep and the more they fought going to bed.
What do we make of this? The researchers suspect that many family bedtime struggles are driven not by the parents’ inability to enforce limits, but by a simple mistake: Parents are expecting kids to fall asleep before their children are biologically capable of doing so. Readjust expectations, and you might solve the problem.
But wait, I hear people ask. What about sleep requirements? If a preschooler has to wake up early, she needs to go to bed early, right? In many families, people are compelled by work and school schedules to wake up before their biological clocks are ready. What should they do?
There are no easy solutions, I’m afraid. But the research conducted by LeBourgeois and her team highlights an important point: Ignoring biology and sending alert kids to bed isn’t the answer. What makes more sense, I think, is to try to give biology a nudge, gradually, by reprogramming your child’s inner clock. Experiments suggest that exposing people to bright light early in the morning (between 6 and 8 am) helps change their circadian rhythms, making the melatonin surge happen earlier in the evening. And steering clear of counter-productive stimulants in the evening – like artificial lights, exercise, negative emotions, and too much excitement – is also crucial.
I wonder what the study population size was. If the sleep cycle can be moved earlier then the kids who have an earlier bedtime could already be on an earlier melatonin cycle? My toddler goes to bed at 7:30 and it usually takes her around 10 minutes to fall asleep. I think she’s genuinely tired and ready for bed at that point.
I tend to believe that most toddlers and babies (and people in general) are not getting enough sleep. If children wake up crying and are cranky then they didn’t get enough sleep (or they have a health problem). I’ve been working with toddlers for the past couple of years and noticed that the parents who report a regular early bed time and (at minimum) 12 hours of uninterrupted sleep have happier, less fussy, more alert and inquisitive toddlers. From my perspective less sleep means a fussy and clingy child. I’m concerned that this article will justify parents to continually put their already sleep deprived children to bed too late.
Great! Another thing to add to the list of a child evaluators to diagnose a kid with .. Parents know when their kids are tired and cranky. And even if they hang out in bed day dreaming let them!! It’s one of the only few moments or “hour” in the day when they can be alone with their thoughts… And this is coming from a mother of 4 boys who would love to have quiet time by 7. But I’m realistic and set sleep times according to age and their behavior for that specific day .. Example my 9 yr old bed time is anywhere between 9-9:45….
Whatever works.
But I don’t believe it’s a cause or wil cause ensomnia. In fact creativity captures their young minds when lying in bed in a calm enviornment like hmmm say there bedrooms!!
I remember spending up to 2 hours waiting to fall asleep every night as a child, and it was very emotionally uncomfortable for me. To have THAT much time to lay there and think in silence wasn’t good for me. I’m not sure what age range this occurred from and to, but I know that I was sent to bed at 7pm and got up at 7pm as an 8 year old child: 12 hours is too much for an 8 year old by today’s charts, so this certainly fits in with the research findings.
It would be interesting to know what the long term sleep and emotional impacts of sending your kids to bed too early are, although I’m sure this would be very difficult to assess.
Very interesting to know that you can be trained to produce melatonin earlier through light controls!
It’s funny because I’ve always thought my daughter had a late bedtime, but no matter what we do she will not go to sleep before 9pm. It’s good to know that there may be a biological explanation for it and maybe she’s fine as long as she’s getting enough rest!
Just to be clear, the point of this study isn’t that people should change their bedtimes. The point is that parents coping with bedtime problems should ask if they are imposing a bedtime that’s mismatched with their kids’ circadian rhythms. Some kids get sleepier early in the evening, others later. Trouble comes when the bedtime is too early relative to the child’s personal DLMO.
I have three healthy kids and teach upper elementary. We don’t have a strict bedtime for our kids and all seem happy. My teen goes to bed sometime after 10, but I require downstairs by 10:30 and gets up at 6:00. My elementary ager goes to bed between 8:30-10:00 depending on what we are doing and gets up at 6:15 even on weekends. My toddler goes to bed when I sat down and rock her after her one nursing a day. All three play hard and our toddler still takes a long afternoon nap. I’m glad something says I’m not doing it wrong.
My son has no set bedtime. He goes to bed when he seems tired. Once he hits that yawning clumsy stage he gets put in his crib. He’s usually asleep within five minutes, though often less. If he gets to the cranky stage it’s because I waited too long. It doesn’t usually get to that stage but it did happen recently when he didn’t want to take a nap (cause he could hear his Dad in the driveway). So I got him out of his crib and took him to the pool for a couple of hours. But again, that’s rare.
I think letting little kids and babies tell you when they need to sleep is the best method. I don’t like the “we need to be up at X time everyday so you’re going to bed at X time”. Yeah I know some families have two working parents and daycare. But what’s the excuse for stay at home families? I’m home for my kid so I can ensure that we have this kind of flexibility. I do believe in consistency and having set times for things, but why can’t the kid set some of them? My kid got stuck on West Coast time and goes to bed between 7:30 and 9pm, so I know after that I’ll have alone time with my husband. And the variation is usually down to what we did that day so on the days he goes to bed “late” we’re happy to have him up with us. Long days mean an early bed time. I’m super set in my ways about some things, but bedtime just isn’t one of them.
Interesting article—my little one goes down at 730pm, bed time routine is about ten minutes and then she’s asleep about 745. We play pretty hard every day and she only takes one hour to an hour and a half nap. She wakes up usually at around 615, comes and cuddles and we get up for the day at 640. I don’t know what the researchers would say, but it definitely fits us as a family and 730 has been her natural sleep time for a while now. She turns into a crazy child if she stays up past that. Luckily, it works for us bc my husband and I both work outside the home.
False. Just because the kids they studied and changed their daily routine by making them wear bracelets and taking swabs of saliva from their mouth in which totally upsets their sleeping pattern because this is not something they have experienced from birth to present does not mean the results are right! My kids have been on a schedule from birth to present and they go right to bed and are out! But that’s ok you can believe everything you read or hear I choose not to and my kids are amazing individuals because of it!