Split nights, what are they?

Is your little one waking up in the middle of the night? I mean, REALLY waking up, and STAYING up. For like….HOURS..

split nights

If you’re the parent of a baby who’s dealing with segmented sleep, you know exactly what I’m talking about. This isn’t the middle of the night “go in and comfort baby for ten minutes until he gets back to sleep” wake up. This is a full-blown 3:00 a.m. dance party.

It’s got a few names.

Segmented sleep.

Bifurcated sleep.

Split nights.

It describes a situation where your little one sleeps for a long stretch, then wakes up happy and energetic in the middle of the night, and stays that way for an hour or more.

This isn’t a new or unnatural phenomenon.

Back before the widespread use of the electric light bulb, people would regularly sleep for a few hours, wake up for another hour or two, then go back to sleep. They’d use the time to read, smoke, pray, have sex (not necessarily all at one), and then after an hour or two, they’d get back into bed, and sleep until morning.

Nowadays, however, the vast majority of us go to sleep at night and aim to sleep until morning time. The kicker is, the baby doesn’t always get the memo. This is actually a pretty common issue. Baby goes down at 7pm at night, wakes at 3am, parties her ass off for an hour and a half, then goes back to sleep. Not a care in the world in regards to the groggy, miserable day Mum and Dad experience the next day.

So let’s take a look at why this happens and then we’ll get to how to solve the problem.

There are two major drivers when it comes to sleep.

There’s our circadian rhythm, which is our natural tendency to fall asleep when it’s dark and wake up when it’s light.

Then there’s our homeostatic sleep drive, commonly known as sleep pressure, which builds up over the time we’re awake.

So ideally, over the course of the day, sleep pressure builds up. Then at bedtime, when the pressure hits the sweet spot, baby puts her head down and goes to sleep. As that sleep pressure begins to subside, circadian rhythm takes over and baby stays asleep until morning.

In the case of a split night, we could be looking at one of two reasons why baby is waking up.

  • Baby’s not getting to bed early enough OR
  • Baby’s going to bed too early

So here’s the deal.

If baby’s getting to bed too late, if too much sleep pressure has built up, the brain has this instinctive response that says “hey, your tired but you’re not sleeping. I better keep you up right, so here, have some cortisol”.

The brain means well but this now means that baby finds it tough to sleep at bedtime as they feel ‘wired’ from the cortisol. It can also cause a full wake up at the end of a sleep cycle, which can commonly happen around 2-3am.


If this is the case, you’re one of the lucky ones. Treat this like any other night time wake up, reassure baby that it’s still bedtime, comfort her and let her get back to sleep on her own, and consider moving bedtime up a bit over the course of a few nights.

Then there’s the alternate scenario. Baby’s getting to bed too early.

In a situation where baby’s getting lots of quality daytime sleep and going to bed early, it’s possible that there’s not enough sleep pressure built up to keep baby sleeping until their circadian rhythm takes over and helps them sleep through the rest of the night, so up they get.

Now that there isn’t as much sleep pressure, and their circadian rhythm doesn’t have the horsepower to get them to sleep on their own, suddenly they’re up and active for an hour (or three!) while that pressure builds back up.

Now, I’m all about early bedtimes. Too little sleep is a much bigger problem than too much.

However, if your baby’s experiencing this kind of split-night sleep, it’s worth looking at their schedule and doing a little fine tuning to ensure that you’re hitting the optimum sleep pressure right at the same time that baby’s going to bed for the night.

There are plenty of situations that can arise where you’ll want to get baby to bed a little early. If she had a day of lousy naps and is clearly tired a half hour before bedtime, it’s absolutely the right move to get her to bed ahead of schedule. However, avoid putting baby to bed early more than one or two nights in a row.

We want to prevent overtiredness but we also don’t want baby in the cot at night for more time than they’re actually capable of sleeping.

So if baby’s had a tough day and didn’t nap well, it’s fine to get her to bed a little early, since that sleep pressure is likely already built up, but try to get her back onto the regular schedule starting the next morning, including her wake-up time.

I know that this can all start to sound like an immaculately choreographed ballet, and in some ways it can be pretty complicated, but the more you understand the nuances and know where to make those minor adjustments, the better your baby will sleep, and the less they’ll run into these regressions, setbacks, and interruptions.

One final thing to consider if you’re getting ready to tackle this situation.

This is not likely to be an overnight fix.

Once baby has gotten into this habit, getting them out of it can take some time.

Like any attachment or dependency, overcoming it is an incremental process. It’s likely to be met with some pushback.

If and when things get tough, remember your goal. You’re giving your little one the skills they need to sleep soundly through the night, and that contributes to their well-being in so many different ways.

Stay consistent, be patient, and before too long your baby and you will both be enjoying full nights of deep, restful sleep.

Have some questions?