When I took my initial deep dive into the infant sleep world, I quickly stumbled upon the term, wake windows. The term you may not know about is biological (bio) sleep times. (I’ll talk more about this later in this post.)

Wake windows are everywhere.  Perhaps you’ve already heard of them yourself.  If you haven’t, wake windows refer to the amount of awake time your little one has in between sleep periods.  So, everything in between like diaper changes, feedings, tummy time, walks, and nap and bedtime routine counts as awake time.   But what isn’t commonly talked about is that wake windows have an expiration date.  

Wake windows work well for guiding sleep periods during the newborn phase because a newborn is still developing their internal clock (circadian rhythm).  But, as your little one graduates from the newborn phase (0-3 months), they also graduate from using wake windows.  This is where biological (bio) sleep times come into play.  This is the case because, at around 4 months of age, you start to see the development of a more mature circadian rhythm.  With a more established circadian rhythm, your newborn has their own hormones and other circadian rhythm factors circulating that aid in the development of natural sleepy periods.

Let me dive a little deeper into how bio times are created.

A person’s circadian rhythm is responsible for a variety of natural and internal fluctuations in a 24-hour period including sleep.  As such, the circadian rhythm is responsible for peaks and troughs of sleep drive throughout the day.  Homeostatic sleep drive (sleep pressure) is the gradual build of sleep pressure that occurs the longer a person stays awake.  With every minute or hour of being awake, the sleep pressure grows stronger and stronger. 

As this pressure continues to build, you are going to see your little one become tired and show sleepy cues.  While independent of each other, the two often align alongside one another.  A “sweet spot” emerges when a child is put down to sleep as the peak of sleep drive coincides with the peak of sleep pressure.  These “sweet spots” are your little one’s biological sleep times.  And it is by putting your child down at these times that will result in quality, restorative sleep.

Following wake windows past their expiration date (around 4 months of age) could push back your little one’s nap and have them miss out on the restorative sleep bio times have to offer.  This can create a domino effect and cause a later bedtime. The result is your little one missing out on the most deep, restorative sleep that happens in the first half of night sleep.  The end result- an overtired child.  

If what you’re doing right now is working and your little one has restorative naps, consolidated night sleep, and appropriate morning wake-ups, don’t change a thing.  But, if you’re using wake windows and see your little one suffering from short naps, interrupted night sleep, and early morning wakings, reevaluating their schedule may be helpful.  If the latter sounds like you, don’t worry, I’ve been there too.  There’s a solution.  

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If you need more individualized guidance on how to manage your infant’s sleep or set up a healthy sleep foundation, book your Discovery Call today!