How cortisol affects sleep, and ways to reduce it for a better night's rest

Did you know that our cortisol plays a key role in our sleep and circadian rhythm?! 

And with the stress of the past few years, it's an important topic right now ❤️

Cortisol (aka stress hormone) and melatonin work in almost perfect opposition to each other

While melatonin prepares our body for sleep, cortisol  prepares our body for action!

Melatonin naturally increases with darkness, peaks overnight, and drops in the morning - whereas cortisol SHOULD do the opposite - drop in the evening, stay low overnight (allowing us to sleep deeply, rest, and recover), and start rising just before we wake up. This is called the cortisol awakening response, and it plays a vital role in preparing us for the day.

Yet when we're chronically stressed and don't allow our body and mind to wind down for sleep, this can mess with our natural hormone levels.

We're going to take a quick look at the science of how our body clock works next, then dive more into cortisol after that, as they're closely intertwined.

So our circadian rhythm and sleep /wake cycle are mostly controlled by our suprachiasmatic nucleus - a tiny area in our brain known as the master clock. We also have ‘clock genes’ in many other parts of our body - our gut, liver, muscle, fat, blood vessels, and heart. For more details check out our post on circadian rhythm here

These genes control what our cells do, depending on time of day - they also follow a 24h cycle, meaning they like to do the same things at the same time each day!

These cells regulate things like our sleep, hormone levels digestion, immune function and even metabolism. The idea behind this is to focus our energy into different things at different times of the day, depending on our activities - our bodies are pretty amazing really!

Cortisol aka stress hormone, is one of THE most potent stimulators of our clock genes, and cortisol receptors are present in almost every cell.

 This is because cortisol helps to transmit signals from the SCN to the rest of our body, telling different body systems when to be active and when to rest. It also regulates our immune system based on the time of the day!!!

Random fact - cortisol actually comes from cholesterol, and progesterone is a precursor, meaning female hormones and stress hormones are closely interrelated . This is part of why stress can play SO much havoc with our hormones - affecting everything from our menstrual cycle, menopausal symptoms, to even our fertility 😳

Cortisol has wide-ranging and varied effects in our body, it:

✔️Increases our blood pressure, heart rate, and breathing rate

✔️Elevates our blood sugar level

✔️Heightens our senses, making us hyperalert and hyperaware

✔️Stimulates our immune function and digestion 

✔️Stimulates metabolism 

All of these are great in the short term, as they allow our body to react and deal with physical and mental stress, and actually helps us perform better, heal faster, and even fight off infection!

Yet in chronic stress, our cortisol fails to drop and follow the natural peaks and troughs, and instead remains elevated… which subsequently disrupts our sleep and circadian rhythm

This can causes insomnia, fragmented sleep and reduced sleep time. That 3am waking with your mind racing or heart pounding is a typical symptom of stress 😬

Sleep deprivation also then stimulates our HPA axis (hypothalamic pituitary axis - the main hormone regulator) to produce more cortisol to try wake up the body, causing a vicious cycle…

This is why reducing stress, improving vagal tone, and boosting resilience to stress is so important for good sleep!

Fortunately there are loads of great ways to help combat stress, help our cortisol levels drop like they're meant to, and get a better night's sleep.

We cover this in more depth in other posts in this section, but one of the quickest easiest ways can be a sleep meditation, breathing exercise or de-stress meditation - why not try the ones we've included in the movement and mind area, and see how it improves your sleep!

These are best done regularly, so don't give up if they don't work straight away - like with many things, good things take time - and science shows that regular meditation can make a massive difference to our sleep ❤️