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Infant and Toddler Sleep Cycles (and the 40 minute mark)

by Whitney Westenberg

Sleep consultant and founder of You Sleep We Sleep

Before I became a mom, I never gave much thought to the science behind sleep, or any of the driving forces in this world and or bodies that help us sleep throughout the night (and for babies, obviously, during the day). An important aspect of sleep to understand before jumping in to the sleep world is infant and toddler sleep cycles!

Just like adults, children also go through wave like cycles of sleep! As humans, we all go through cycles of sleep through the night. Experts say we go through 4 stages of sleep, the first 3 being non-REM (1 and 2 relatively light stages, 3 being the deepest stage of sleep) and the 4th REM stage, where we experience dreams!

SO - newborns basically have 2 sleep cycles : active sleep and quiet sleep, where they spend up to 50% of their sleep in REM sleep, compared to an adult’s 20%. Around 4 months, babies will start to regulate melatonin production, thus their sleep cycles begin to change, and will start experiencing more lighter stages of sleep. It’s not until the age of 5 that a child’s sleep cycle will actually start to mirror that of an adults’.

A sleep cycle of an adult lasts about 90 min - but that of an infant or a toddler (4 months to 4 years), is around 40 to 60 minutes! Have a look at this chart, which shows the stages of sleep your little one hits within those 40 to 60 minutes. It’s broken down into these stages:

Stage 1 - 0-10 Minutes : starting to fall asleep

Stage 2 - 10-20 Minutes : falling into deeper sleep

Stage 3 - 20-30 Minutes : heavy sleep

Stage 4 - 30- 40 minutes : coming out of heavy sleep

Stage 5 - 40-60 minutes : light sleep, easy to wake

SO - onto the reason why you probably came to this blog in the first place - the 40 minute mark! Although, for some of my parents out there, it could be more like 30 minutes!

Now as adults, normally when we transition through sleep cycles, we can roll over, adjust our covers or our pillows and fall right back asleep, no big deal…we probably can’t even remember it in the morning! When your little one transitions through sleep cycles, I can almost GUARANTEE you, that they will stir - what I love to call the “40 minute mark”! Most likely, they will pop their head up, have a look around, check to see if everything is as it was when they initially fell asleep, then doze back off.

NOW - let’s say baby has been rocked, fed, or nursed to sleep and wakes up? They will most likely need that SAME THING to get them BACK to sleep. So, if your can help your little one fall asleep independently, the chances of them being able to lay their heads back down and fall back asleep unassisted will be much higher!

Most babies have not yet mastered this skill of falling asleep without the help of mom or dad AND THAT’S OK! Practice makes perfect - I encourage you to practice putting your little one down AWAKE. I know….that sounds easier said than done….so here are some tips you can try! :

  1. Keep the lights on in their sleep environment during that last feed before bed, whether it’s bottles or nursing, to try to keep them awake. When it’s time to wind down, I strongly recommend dimming the lights, to help set the mood/tone for bedtime.dringend, das Licht zu dimmen, um die Stimmung für die Schlafenszeit zu verbessern.

  2. Help your kiddo learn to fall asleep independently - this could also be another reason they are constantly waking if they are falling asleep heavily assisted. Practice laying baby down awake and help them soothe with some shush-patting and the comfort of your voice.

  3. Follow age appropriate wake windows, to ensure your little one isn’t under tired or overtired. In my experience, an overtired baby (aka, a baby who has been awake too long before the next nap) will most likely wake at that 40 minute mark and refuse to go back down!

  4. More key factors in helping your baby fall into that next sleep cycle is perfecting the sleep environment :

- make sure it is DARK - any light coming in can distract baby if he/she happens to wake up, and make it EVEN HARDER to fall back asleep

- turn that sound machine ON, also for naps! Most babies and toddlers find quiet actually more disturbing - white noise will help emulate sounds from mama’s womb and create a calming effect

- keep the room cool, 19C (68-72F)— babies can easily over-heat and this can be very uncomfortable, not to mention dangerous

So…what to do when baby wakes at the 40 minute mark? First of all - I want your to EXPEXT that your baby will wake at this mark (especially during naps!). Don’t panic, first, watch and listen….you may be surprised! Give your little one some time to settle, don’t rush in! More often than not, they can fall back to sleep on their own. If, and you’ll feel it in your gut, baby needs you, go in and offer comfort and help them fall into the next cycle. Once your little one has calmed or has fallen back asleep, you can exit the room. Little tip - you can wait 10 minutes to leave, that way, you are more or less sure that babe has fallen into a deep cycle of sleep.

If your kiddo constantly waking at the 40 minute mark, and you are struggling to get them to sleep or nap beyond this point, I would LOVE to help you find a solution! Have you tried my tips above and are still not sure what could be the underlying factor?

Click here to book your free 15 minute consultation and let’s figure out how we can help your little one connect those sleep cycles!

As a certified sleep consultant, I can help you pinpoint your child’s sleep needs and issues.

I hope this little extra side of science gave you a little more insight today in the world of infant and toddler sleep! Good luck and sleep well my friends!

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