Circadian Rhythm

Sounds dull doesn’t it but honestly when you understand this shit lots of things make sense! I want to help people understand this stuff in a way that’s easy to digest and helps educate you on the science of sleep without boring you to death or confusing you even further.
The training course I took to become a sleep consultant was science and evidence based and it was understanding that which made me realise why I had all the issues I had with my own little ones sleep.
Although we are all different there are a few things about our biology that is the same – like hormones!
I think sometimes it’s easy for us to forget that babies are still humans, I mean yes they are pretty helpless ones that need our entire attention to keep them safe but they have the same basic needs as us – love, safety, food, light, social interaction and sleep.
A lot of times when clients come to me I can tell straight away why they aren’t sleeping at night and often it’s to do with how much they are awake and asleep in the day. These are all important pieces of the puzzle in figuring out the best solution. As we work together I put them on an age appropriate schedule and then as time goes on we find what the child’s natural rhythm is.

What the heck is a circadian rhythm?

Also known as the body clock, the circadian rhythm is our natural sleep-wake pattern and is controlled by hormones called Melatonin and Cortisol. The hormone Melatonin basically helps us to sleep and is produced in darkness, hence why we sleep with the light off and that needs to happen for babies as well. Cortisol rises when light comes into the room and helps to wake us up.
Food also helps to set our rhythm which is why if you’re still feeding a baby at night time when they aren’t genuinely hungry they will still wake looking for that because the circadian rhythm is set to wake then, so even when you drop the feed you may still get wakes at those times for a while until babies body clock adjusts.
We aren’t designed to eat at night and doing so can be confusing and so it’s best to drop those feeds as soon as you can if baby is over 4 months and of a healthy weight.

The role of circadian rhythm and early morning wakes

Because light and social interaction wakes us up and makes it harder for us to get back to sleep, when you have a child that is waking from 4am onwards, if they then have a feed and/or you go and interact with them, they can become wide awake. You then decide they have no chance of falling back to sleep and get them up – you’re setting their rhythm that it is morning time now without even realising it.
This is why it’s best to keep interactions to a minimum in these early hours, avoid feeding and treat it as a night wake so that they learn to go back to sleep.

Why is it so important?

When properly aligned, the circadian rhythm can promote consistent and restorative sleep. This is why going to sleep at the same time each night and waking at the same time each morning really is the best thing for you.
Broken sleep, inconsistent sleep, lack of sleep will have a negative effect on your physical and emotional wellbeing. Babies do all their growing and development in their sleep, this process can be affected if they are having broken sleep and not enough day sleep.

Healthy sleep hygiene

‘Sleep is brain food: healthy sleep is like healthy food’ Marc Weissbluth
This is all about giving yourself and your child the best chance of sleeping well each night. Often I talk to parents who just accept their child doesn’t sleep. There are actually lots of things you can do to improve sleep and sometimes the smallest change can make the biggest difference.
The first thing you need to do is prioritise sleep, understand how important it is for your wellbeing and that of your family and make a point of ensuring you get the same amount of sleep night after night.
For babies lots of this starts with the sleep environment, setting yourself up for success here will give your child the best chance of settling well and staying asleep for longer.
As discussed earlier, get the room pitch black as darkness helps to produce Melatonin, ensure the room temperature is between 18-20c, babies core body temperature dips around 3/4am which can cause them to wake as well. Use white noise from birth to help trigger the calming reflex and use a swaddle as well.
For info on sleep environment see my YouTube video here.
Get bedtime consistent, have a wind down routine that lasts about 30 minutes and helps to get baby into the mood for sleeping. Doing this every single day helps to set baby’s rhythm that this is bedtime and sleep becomes more predictable.

How can I best use the circadian rhythm to encourage more sleep?

The number one thing you can do that helps find your babies natural sleep phase is to watch awake windows, ensuring these are age appropriate makes it more likely your baby is genuinely tired when you’re trying to get them to sleep. If you don’t know what they are, you can grab my FREE Nap Guide here.
Awake windows will increase as your baby grows, so it’s useful to have a guide so you can keep adjusting them. Doing this helps to catch them when melatonin is high and before cortisol kicks in and makes them overtired which will cause them to fight sleep and sleep less overall.
If you do this during the day that then sets bedtime at an appropriate time as well and will help with night sleep. Since babies only need so much sleep across a 24 hour period you need to ensure they are getting the bulk of this at night-time.
TOP TIP: Get baby up at the same time every morning regardless of how they slept during the night so that you set their rhythm to wake at the same day, this then also helps you to get the right mount of day sleep in for their age and set bedtime at an age appropriate time.


The Circadian Rhythm is your babies natural sleep-wake cycle and it is set by food, light and social interaction. We are designed to sleep at night time but if this natural rhythm is messed with for e.g. by feeding baby multiple times at night or exposing baby to light at the wrong times it can become completely out of alignment for their needs.
The hormones that govern the circadian rhythm Melatonin and Cortisol are easy to work with if you know how. Darkness helps produce melatonin and putting your baby to sleep when melatonin is naturally high will help them to settle quicker and sleep for longer.
Use awake windows to know when this is rather than guessing or waiting for tired signs as that can be too late. Cortisol can stay high all day and into the night causing multiple night wakes that are long in duration.
If you’re struggling with early morning wakes make sure you do not get your child up before the desired wake up time, otherwise you are setting their body clock to that early time and it can reinforce the early wake the next morning.
If you’re wanting to get on more of a structure with your child but don’t know where to start my Routine Guides are only £20 and give you a feed/nap routine that’s age appropriate from newborn to toddlers age 3. Click here to grab one now.