Body clocks and their influence on sleep...

The circadian rhythm in babies (4 ways to boost sleep)

Feb 11, 2022
4 min read

You might have heard us talking about using a very dark room for baby's naps and night time sleep. And by dark we mean, TOTALLY pitch black. Perhaps you've seen that we (and other baby sleep experts) suggest waking your baby at the same time every morning. While some think this sounds a bit extreme, we have very good reasons for our recommendations and they all stem back to our physiology as humans...

Understanding the body clock

Human beings are mammals that are governed by a set of elemental "rules" just like any other mammal. That is, our bodies, on a primal level, react and respond to natural cues in our environment (called zeitgebers) and these cues allow our body clocks to function properly.

The biological processes we go through day to day, processes such as waking up, feeling hungry, getting tired, going to sleep are controlled by a complex network of hormones and chemicals, which are produced and released at certain times of the day, in response to things like light and dark, hot and cold and of course time. It's called a body "clock" for a reason!

Light, melatonin and sleep

The way humans used to live and some pockets of traditional culture still live, was far more appropriate to how we were built to function, than the way our modern civilisation lives today. In a traditional sense, without electricity and the ability to artificially create and extend daytime with electric lights, we would have woken with the rising of the sun - the sunlight being one of the key body clock triggers (and this would have been at about the same time each day). Then as the day wore on and the sun started to set, we were naturally exposed to diminishing light and this allowed the gradual rise of certain sleep hormones in our body, like melatonin. As the sun vanished, our core body temperatures would also have lowered, further signalling to our body clocks that night was approaching and we would start getting sleepy. Once it was dark, without the ability to prolong daylight, we would sleep. At about the same time each day. And we would sleep well - just think how dark a cave or a mud hut would be. Melatonin is the hormone that helps us fall asleep and stay asleep and it is only produced in the dark. It is then pumped through our bodies until midnight, when levels start to fall and it has gone from our system by the time we wake up.

This is how humans are built to operate. As organic beings, we are (well, we should be) totally in tune with the natural rhythm of things. 

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4 ways to help your baby’s circadian rhythm

The problem is, these days, our body clocks are broken. Through technology and invention we have outsmarted our biology. We no longer respond to the sun going down in a physiological way - we simply turn on the lights. This in itself, instantly halts the natural process our bodies should be going through to prepare for sleep and all the hormones are put on hold. We also often have quite varied wake times and bedtimes. This is why there are so many sleep issues around today in adults and children alike.

So, how can we help our babies (and maybe even ourselves)?

1. We can recreate a cave.

So to speak. We can create a nice dark environment for sleep which, we know, promotes good sleep hormones. It is proven that sleeping your baby in a very dark room leads to easier settling and longer naps. Even using a night light will be stimulating for your little one and can inhibit their ability to settle well. We can create a "cave" for daytime naps as well as night time sleep with the use of things like blackout blinds - ensuring our babies have the best chance of a decent restorative rest.

2. Let the natural light in.

When your baby wakes in the morning, open their curtains and let the natural light signal that it's daytime. This will help lock in a consistent morning wake time. If your baby has an early morning waking habit, it might actually be caused by sunlight in the first place, so check your baby's curtains aren't letting any light through at 5am. While we want to be as biologically responsive as we can when it comes to baby sleep, the way our modern lives have to operate means that 5am isn't always a reasonable time for the household to wake!

3. Dim the lights in the evening.

A good way to help your baby get ready for sleep is to let them be controlled by the natural process of going to sleep - resisting turning on the lights in the early evening and having quiet wind-down time is a great way to help keep that body clock counting down to bedtime.

4. Have some structure. 

As well as light and dark, our body clocks were traditionally regulated by predictable activities, such as regular meal times, regular patterns or activities in our day which formed a solid routine. It is a common view that "traditional parenting" means not following a routine and letting your baby dictate the pattern of the day, but the contrary evidence of this is in looking at the way our ancestors used to live and the way pockets of traditional cultures still live. These people have very structured routines to their day - they have to - waking with the sun, eating together, hunting, stopping for food at specific times. Days are predictable; they are incredibly routine. The babies are waking and sleeping at the same times each day as a result of the cyclical nature of their people, who operate in this way because it's how they survive. It is, if anything, a far more structured and predictable way of life than we have in modern society and reinforces why we see again and again that babies and children thrive on a predictable routine - it is how we are built.

And it's how we've written our Sleep Programs. We really understand sleep processes and our Programs are based on the natural rhythm of your baby's day which includes establishing consistent bedtimes, consistent wake times, utilizing that biological need for predictability in order to effectively set our somewhat broken body clocks. 

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Iwata S, Fujita F, Kinoshita M, Unno M, Horinouchi T, Morokuma S, Iwata O. Dependence of nighttime sleep duration in one-month-old infants on alterations in natural and artificial photoperiod. Sci Rep. 2017 Mar 17;7:44749. doi: 10.1038/srep44749. PubMed PMID: 28303945; PubMed Central PMCID: PMC5355994.

Mindell JA, Li AM, Sadeh A, Kwon R, Goh DY. Bedtime routines for young children: a dose-dependent association with sleep outcomes. Sleep. 2015 May 1;38(5):717-22. doi: 10.5665/sleep.4662. PubMed PMID: 25325483; PubMed Central PMCID: PMC4402657.

Coons S, Guilleminault C. Development of consolidated sleep and wakeful periods in relation to the day/night cycle in infancy. Dev Med Child Neurol. 1984 Apr;26(2):169-76. PubMed PMID: 6724155.

Small, M. F (1998). Our Babies, Ourselves: how biology and culture shape the way we parent. Random House: Anchor Books.


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