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Wake windows – what are they and why are they so important?

If you've been researching baby sleep or follow a sleep consultant on social media, you will have heard the term 'wake window' being mentioned and you may be thinking, what on earth is a wake window?

In short, a wake window is the period of time between two sleeps. This can be between two naps or a nap and a nighttime sleep and it is your child's capacity to stay awake between these sleeps.

Wake windows lengthen as your little one gets older and the number of wake windows will change depending on how many naps your little one is having during the day. Wake windows can be used to help calculate when your little one should be having a nap and are crucial when it comes to getting a good nights sleep.

When looking at wake windows we have two things we want to avoid:

1) Putting an undertired baby down to sleep - as they are not tired enough to sleep


2) Putting an overtired baby down to sleep as it can make settling tough and it can affect their ability to sleep causing cat naps and overnight wakings.

To fully understand the importance of wake windows, I wanted to talk a little bit about the science behind sleep. When it comes to sleep, there are two key hormones that we need to take into consideration: cortisol and melatonin.

Cortisol aka the wake-up hormone is needed to allow us to rouse and wake up naturally. If we didn’t produce cortisol, we wouldn’t get out of bed in the morning, so it is a really important hormone for our brains to produce.

However, if we become over-tired, our bodies can start to make more cortisol, which means it's even harder for us to drift off to sleep in a soothing and relaxing manner. For children, this can mean they start resisting sleep and become grumpy, fussy or even start crying.

As adults we sometimes do this too, think about those nights when you’re tired but just cannot get to sleep and how frustrating that is. Now imagine someone has kept you awake past your capacity to be awake, you'd get pretty upset too, wouldn't you?

As parents, we don't intend to make our kids overtired, but it can happen if we don't fully understand their capacity to be awake and allow them to get the sleep they need, when they need it.

Melatonin is needed for sleep and is facilitated by darkness. It helps us to regulate our circadian rhythm (our 24 hour internal clock) and is produced in the earlier part of the night when we are in a deeper sleep.

Having a dark sleep environment and a regular routine is key to supporting melatonin production.

One thing to keep in mind is that babies can’t produce melatonin for the first few months of their life.

Why are wake windows so important?

As you just read, when a little one becomes overtired, their bodies produce more cortisol, and this can make it difficult for them to settle and sleep.

As well as babies/toddlers finding it difficult to settle at bedtime/nap time, the build-up of cortisol in their body won’t disappear immediately, leaving a more-than-normal amount overnight which can then lead to wakeups in the night and/or lighter (less quality and less restorative) sleep.

By understanding a little one's wake window, we can ensure they are in their sleep environment at the optimal time to reduce the risk of going into an overtired state.

Below is a guide that shows what the ‘ideal’ wake windows are based on age. Of course, in some cases these may need to be adjusted, for example, if your little one has had an extremely stimulating wake window, you may find that they need to have their nap a little earlier. So, remember to look out for your baby's sleep cues too.

Making sure your little ones wake windows are correct for their age is the first step to a good nightnight'ss sleep.

If you would like an app to help you track your little ones sleep, I can highly recommend the BabyFeedTimer app

This is the app we used with our baby and it is super handy for logging wake windows

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