Did you know that cortisol plays a key role in sleep and circadian rhythm?!
And with the stress of the past 18 months, 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!
The circadian rhythm and sleep /wake cycle is mostly controlled by the suprachiasmatic nucleus (a tiny area of the brain known as the master clock)
.
However clock genes are also present in many other parts of the body - gut, liver, muscle, fat, blood vessels, and the heart
These genes control cell activity depending on time of day, and also follow a 24h cycle
They regulate things like sleep, hormone release, immune function and metabolism
Cortisol is one of the most potent stimulators of the clock genes, and receptors to it are in almost every cell.
It helps to transmit signals from the SCN to the rest of the body, telling them when to be active. It also regulates the immune system based on time of day
Cortisol actually comes from cholesterol, and progesterone is a precursor, meaning female hormones and stress hormones are closely interrelated
Cortisol naturally peaks early morning an hour after waking, and plays a vital role in Wakefulness
In a non stressed situation it follows a predictable curve over the day, but will also go up for short bursts in response to any physical or emotional stress
Cortisol :
Increases blood pressure heart rate, and breathing
Spikes blood sugar
Heightens senses
Stimulates immune function and digestion
Stimulates metabolism
In chronic stress however cortisol fails to drop and remains elevated, , which then disrupts sleep and the circadian rhythm
This causes insomnia, fragmented sleep and reduced sleep time.
Sleep deprivation stimulates the HPA axis 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!
Int J Environ Res Public Health. 2021 Jan; 18(2): 676.
doi: 10.3390/ijerph18020676
https://www.healthline.com/health/cortisol-and-sleep#ways-to-lower-levels