Does sleep beget sleep? Naps, later bedtimes and early waking
Does sleep really beget sleep? Three questions about naps, later bedtimes and early morning waking — and why the honest answer to each is “it depends, and here is on what”.
Short answer: does sleep beget sleep?
- Partly. A baby who sleeps well in the day usually sleeps better at night, but the effect has limits and it works differently for different babies.
- Waking your baby from a nap helps if the nap was ending too close to bedtime. It backfires if it makes him overtired — and overtired babies often get hyper rather than sleepy.
- A later bedtime helps only if the old bedtime was too early. If bedtime was already right, pushing it later makes falling asleep harder for some babies and easier for others.
- A later bedtime usually does not buy you a later morning. Most babies wake at the same time regardless, and some wake even earlier, because they miss a whole sleep cycle.
- You can shift the whole schedule later, but it takes weeks of consistency, and you have to move the naps and feeds too, not just bedtime.
Would you like to listen to a podcast episode about this? Sleep begets sleep?
Does sleep beget sleep?
There's a concept in sleep coaching that is “sleep begets sleep”, or “sleep promotes sleep”. It means that if a baby sleeps better during the day, then he will sleep better at night, and vice versa. When he sleeps well at night, he will have more restorative naps. Or the more he sleeps, the more he sleeps, right?
Today I collected 3 questions around this concept.
Should I wake my baby from a nap so he sleeps better at night?
Okay, so here's the first question: "Will my baby sleep better at night if I wake him up from his nap?" Okay, so it depends. You will see that the answer to these questions will always be "it depends," but it doesn't mean that you cannot know, okay? So, first of all if your baby's last nap is too close to bedtime, that is not good, because the baby won't be properly tired or sleepy when it's time to go to bed for the night, and that might cause difficulties in falling asleep. Or if the baby falls asleep easily, it can still cause problems during the night.
It can happen that the baby wakes up more often or earlier than usual. So when you plan your schedule, try to make enough time between the last nap and bedtime. And this "enough time," of course, depends on your baby and his or her age, okay? So if your baby tends to sleep longer, then try to wake him up before this time.
But what happens if this is not the case and you just wake your baby up for some reason, because you have an errand to run or something? It is true that if you wake your baby up, then he can get overtired. So even if it's not the last nap, it can happen that the baby will accumulate some sleep deficit during the day, and instead of making up for it during the night, it will just cause worse sleep. But it depends on the baby.
Some babies can tolerate these disturbances quite well, and if they get less sleep during the day, they will just sleep longer at night. Or they will just sleep in in the morning. Or they will just easily fall asleep earlier in the evening, and they make up for this deficit. But other babies are different.
Some babies actually get overtired, and when they are overtired, it makes them more difficult to fall asleep. Some babies become hyper and seem to be quite excited, and seem to be just the opposite of tired at bedtime. And that's because overtiredness or tiredness, really, has this effect on some babies. And it's not rare.
So, I mean, if you see your baby running around excitedly just before bedtime, it might be the case that you missed the opportunity to put him to bed at the right time. And then it will be more difficult to put him to bed at that stage. So the answer to this question is that if you wake your baby up because the end of the last nap gets too close to bedtime, then it will probably make bedtime easier and probably make the night better. But if you wake your baby up and it makes him overtired, and he's the type of baby who gets too excited when overtired, or hyper when overtired, then this will cause problems with bedtime.
Will my baby fall asleep easier if I keep him up later?
Okay, second question: "Will my baby fall asleep easier if I keep him up later, or will he get overtired?" Okay, so the answer to this question is also "it depends." So let's imagine there is a toddler with an established schedule. But with this schedule, it takes him too much time to fall asleep in the evening. Too much time means, let's say, more than 15 or 20 minutes. Usually, if bedtime is at the appropriate time for your baby, for your child, then he or she should be able to fall asleep within 15 minutes.
Okay, so if it takes longer than 15 minutes, can you shorten this time by pushing out bedtime later? Okay, so if this inability to fall asleep was caused by too early a bedtime, so in other words your child was not sleepy enough at bedtime, then basically what you can do is you adjust your schedule and you push bedtime later, and that should make your baby fall asleep easier. For example, if bedtime was half past 7, but it usually takes your baby 1 hour to fall asleep, and he actually falls asleep at half past 8, then you should put bedtime at half past 8 and see if your baby falls asleep instantly, or within 15 minutes. The other thing is that children actually get used to the fact that it takes so long for them to fall asleep.
So if this has been going on for weeks or months, that you wait for your baby to fall asleep for an hour, then it can become a habit. And even on occasional days, when your child is more tired than usual, it will still take this much time for them to fall asleep. So this habit might not disappear right away. So even when you push your bedtime at half past 8, it might take some time for your baby, it might even take an hour or so for your baby to fall asleep.
And it's not just a habit. Your baby might have developed this association that going to bed is not good, because he has to be there while not being sleepy, and they are bored. Or very often, older children develop these nighttime fears, which are completely normal for 2, 3, 4 years of age. But if they have more time to worry between going to bed and falling asleep, then these nighttime fears can be exaggerated.
So they might develop this resistance against bedtime because they know that it is difficult for them to fall asleep, and it can become their thing. And this habit can take some time to disappear. So this is one case when a later bedtime can actually help. But what if your bedtime is appropriate and your baby usually falls asleep within 15 minutes, but you still push your bedtime later?
Will your baby fall asleep easier? That depends on your baby, okay? So if the original bedtime was appropriate, then what happens is that your baby is more tired at the new, later bedtime. And some babies react to this by becoming hyper, as I earlier mentioned, and for them it will actually make it much more difficult to fall asleep.
While other babies, they will just take any opportunity they can at that point to fall asleep and will actually fall asleep much easier. So if you think that your bedtime is at the right time, then maybe if you have outings or if you go for a dinner or a party or anything, you will see how your child reacts. And if he becomes hyper, and if it makes it more difficult for them to fall asleep, then you might want to cut back on these outings. But if you're lucky enough and your child doesn't mind and will just fall asleep right after getting home, then of course there's not much harm in getting home later on some days.
Will my baby wake up later in the morning if I put him to bed later?
Okay, last question: "Will my baby wake up later in the morning if I put him to bed later?" Okay, this is a very common one, because babies tend to wake up quite early. And especially for parents who are night owls, this can be very painful. In the sleep coaching literature a 6 a.m. wake-up is considered normal, but that might still be too early for many parents. But it's actually quite usual that babies wake up as early as 5 a.m., which would be, I think, too early for most people.
Okay, so before I answer this question, I have to mention that there's a thing that the last sleep cycle is usually missed by parents.
The last sleep cycle that parents miss
So very often, parents treat the last wake-up between sleep cycles as morning wake-up, because it's close enough to morning, and also the sleep drive to go back to sleep is lower for children at the end of the night. And so parents think that, well, the baby just woke up for the day and then they start their morning routine. So if your child usually wakes up very early in the morning, and then just, like, half an hour or an hour after waking up goes back to sleep, and you count it as the first nap, then chances are that it wasn't the first nap of the day, and that wake-up should have been treated as a nighttime wake-up. So however you decided to treat nighttime wake-ups, whether you feed your child, whether you sleep train your child, just treat the last wake-up, the very early morning wake-up as a nighttime wake-up, and then your kid will go back to sleep for another hour or so, maybe more.
In the short term: three kinds of babies
Okay, that said, if that's not the problem, but your baby just habitually wakes up quite early, then the question still remains whether you can push this wake-up time a bit later by putting the baby to bed later. And there are two answers to this question. The first is short term. So in short term, it depends on the baby, again.
So there are some babies, and I think this is the minority. So there are some babies who can sleep in. So they need their 11 hours of sleep during the night, and if you put them to bed later, they will just sleep longer, until they get their 11 hours of sleep. That said, this only works up to a certain limit.
So like, if you put your baby to bed in the evening, like, 4 hours later than usual, then it's unlikely that he would sleep 4 hours later. But still, there are babies who would sleep, like, an hour or two later than usual. But there are the other type of babies who will wake up the same time every day. So whatever their bedtime, they will just wake up exactly the same time every day.
And even there are babies who will actually wake up earlier in the morning if you put them to bed later.
What I found when I experimented with my daughter's bedtime
This is exactly what happened with my daughter. So when she was waking up at 5:30 a.m., I experimented with her bedtime. And for a week, I've written down every day the exact time when I put her to bed. And I varied it around her usual bedtime.
So some days I added 15 minutes, other days I put her to bed half an hour earlier. On the next day, I put her to bed half an hour later. And I varied her bedtime quite randomly. And I also registered her wake-up times the next day, of course.
And at the end of the week, I tried to fit a line on this data, and what I found is that actually the later she went to bed, the earlier she woke up. So the reason for this could be that when she goes to bed later, she misses a whole sleep cycle. So let's say that her usual bedtime is 7 p.m., and she wakes up usually at 6 a.m., and her sleep cycle is, let's say, 40 minutes. So when you put her to bed at 7:20 p.m., then she will not sleep until 6:20 a.m., but instead will wake up 20 minutes before 6 o'clock, and then she would miss one entire sleep cycle.
And the reason can be that in the morning, when she wakes up before her last sleep cycle, it's already morning enough for her to wake up, and it's already difficult for her to fall asleep, since this wake-up time between sleep cycles is closer to her usual wake-up time, so she won't go back to sleep for her last sleep cycle.
How to test your own baby's bedtime
So if you want to make a little change to your baby's wake-up time, like less than half an hour, I would say, then experiment with this. Just write down the bedtime and the wake-up time for a week, and deliberately choose different bedtimes for every day. But do not do it in a way that you consistently push bedtime later or earlier, but do it randomly, so that the baby doesn't get used to it, and see what you find. Put it on a graph.
I am a nerd, I know: I have a degree in biology, so I love to deal with data. So what I would do, I would just put bedtime on the horizontal axis and wake-up time on the vertical axis, and visualize the data and see whether the line that fits the data — you can do this in Excel — increases or decreases, right?
In the long term: how to shift the whole schedule later
Okay, but then what happens if you want to push wake-up time more than half an hour, like an hour or maybe 2 hours? Okay, so you can actually push wake-up time later if you're consistent enough with the later bedtime. So what I would do, if you want to make bedtime, let's say, an hour and a half later, I would push bedtime half hour later, but not only for a few days, but at least for a week. And then would push bedtime later, either continuously every day or in increments: push it half an hour later for one week, one hour later for the second week, and one and a half hour later on the third week.
So it is actually possible to get babies to adjust to a schedule where everything is later. But in this case, make sure that you also adjust everything during the day of the baby. So not just bedtime and wake-up time, but also all the feedings, all the naps, because otherwise it wouldn't work. And if you do it for long enough, you should be able to shift the entire schedule later in the day.
Frequently asked questions
Does sleep beget sleep?
Up to a point. A baby who naps well is usually easier to settle at night, and a baby who sleeps well at night naps better — but this does not mean more day sleep is always better. A nap that ends too close to bedtime leaves your baby not sleepy enough, and that ruins bedtime rather than helping it.
Should I wake my baby up from a nap?
Yes, if the nap regularly ends too close to bedtime, or if it is so long that it pushes the whole schedule out of shape. No, if waking him simply cuts his total sleep and leaves him overtired. Which of the two happens depends on your baby: some make the deficit up at night, others become hyper and then cannot fall asleep at all.
Will my baby wake up later if I put him to bed later?
Usually not. A minority of babies do sleep in and take their eleven hours whenever they get them. Most wake at the same time no matter when they went to bed, and some wake even earlier — because a later bedtime can make them miss an entire sleep cycle at the end of the night. It is worth testing on your own child rather than assuming.
How do I shift my baby's wake-up time later?
Slowly and consistently. Move bedtime half an hour later and hold it there for a week, then another half hour the following week, and so on. Shift the naps and the feeds by the same amount, not just bedtime — otherwise the day pulls the night back to where it was.
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