What does it mean to “sleep like a baby”?

Have you ever wondered, “Who on earth came up with the phrase ‘sleep like a baby?'”

Did they have NO IDEA how babies sleep?

If those thoughts have ever crossed your mind, you’ve probably interpreted “slept like a baby” to mean “slept well”. And you’d have company; Merriam Webster defines it exactly that way: “to sleep very well”.


Sleeping well?

Let alone very well?

This may be perplexing. Let’s dig into this. How do babies sleep?

Baby sleep is typically tumultuous starting pretty much right after birth.

You may have heard of the infamous “second night syndrome,” the phenomenon where a newborn sleeps fairly well the first night after birth and then barely at all the second night. This change from “recovery sleep” to adjusting-to-the-outside-world sleep can be rough for parents, especially those recovering from giving birth or those who are feeding the baby. In fact, second night syndrome has prompted such article titles as “8 rules for surviving the hell that is second night syndrome“, and the tamer but as ominous, “Are you prepared for your baby’s second night?“.

So, technically, “sleeping like a baby” could refer to the recovery sleep of night 1 on the outside or to the generally tumultuous sleep of night 2 on the outside. But perhaps the first few days of life on the outside isn’t the right age range to think of. The adage indicates a “baby,” which could mean an older baby.

Older babies do tend to have better sleep habits than newborns, but even then, waking up through the night is normal. According to a study that relied on a survey of parents about child sleeping behavior, 84% of six-month-olds did not sleep through the night without waking up, and 16% of them had “no regular sleeping pattern”.

Photo by Tim Bish on Unsplash


Most people probably wouldn’t classify that as “sleeping very well.”

And these results are not just coming from tired parents underestimating the quality of their children’s sleep. According to a video study, babies wake up an average of:

  • 2.9 times per night at 3 months old,
  • 3.5 times per night at 6 months old,
  • 4.7 times per night at 9 months old, and
  • 2.6 times per night at 12 months old.

Keep in mind that in this study, a wakeup was defined as being awake for two or more minutes more than 10 minutes after initially falling asleep, whether the child cried or not and whether an adult intervened or not. Doesn’t sound like great sleep, if you ask me.

A quick video I made with the results of that study.

And even at 12 months old, babies are only self-soothing for about half of their wakeups; the other half involve parents or other caretakers intervening.

So the idea that “sleeping like a baby” means “sleeping well” seems unsupported by evidence on wakeups, regardless of the age range of said baby. #NormalizeBabiesNotSleepingThroughTheNight. #CheckInOnYourParentFriends.

Another hypothesis about this saying is that “to sleep like a baby” means to sleep carefree or untroubled rather than to sleep well.

The thinking behind this interpretation is that babies don’t have to worry about who will get that promotion at work, whether they correctly interpreted that snide remark from a friend, or whether their significant other actually took out the trash like they said they would.

So sleeping like a baby should mean sleeping carefree, right? Actually, no. Babies can worry a lot. Adjusting to the outside world, and then adjusting as their body grows and their world becomes bigger and bigger…that’s a lot to process. If you’ve ever had a language immersion experience in a language you didn’t know, you know that that situation can be super stressful. Or if you’ve ever had to adjust to a new way your body worked, you know that that situation can be super stressful. Babies are pretty much doing both of those things, all the time.

AND in addition to what’s going on with them, babies can pick up on parents’ stress too. Which is yet another reason why taking care of parents is so, so very important. So I’m unsure of this interpretation of “sleep like a baby” as sleeping carefree.

(Could you do me a favor and skip this section if you are experiencing some grief right now? Catch me at the next header!)

One reddit user hypothesizes that the phrase actually means sleeping deeply, even if there are lots of wakeups. This theory is that the phrase originated from another phrase, “to sleep like the dead”; that metaphor traces back to the 1660s, and the jump from “sleeping like the dead” to sleeping like babies only dates back to 1819 in this user’s research. Sleeping like the dead would mean “impossible to wake up,” which isn’t exactly true of babies, as I (and anyone else who has ever reclipped a nursing bra in the presence of a sleeping newborn) can attest.

I wondered if maybe similar metaphors would help me understand,

so I looked into the history of the phrase “to sleep like a log,” which makes even less sense than “to sleep like a baby,” given that at least babies do actually sleep on occasion. (For the etymology geeks out there: the metaphor “to sleep like a log” has a much longer history in Spanish than in English, where it’s only been in use since the 1800s.) “To sleep like a log” apparently generally refers to the peacefulness of a forest (or, at least, the peaceful life of a log in a forest; don’t get me started on how the predator/prey relationship would make one reconsider this metaphor). My, ahem, rabbit hole research into sleeping like a log therefore shed little to no light on my quest to understanding sleeping like a baby.

So, in conclusion, what does it mean when we say, “sleep like a baby?”

Who knows?

My best answer for you is from Bob Dole, who famously explained after losing the 1996 U.S. presidential race, “I slept like a baby. I woke up every three hours and cried.”

If your baby doesn’t sleep through the night, you’re not alone. Remember, you can join other parents in online community at the Mother Well postpartum group every Monday night at 8pm EST.

I wish you all restful naps.

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