The Circadian Rhythm- the ancient biology of sleep health and metabolism

What’s the last thing you do before getting under the covers at night?

Many of us set an alarm.  We say goodnight to a loved one.  We check our social media just one last time.  Maybe we have one, two devices on while we sleep.  Maybe the sweet sound of rain or breaking waves plays to lull us into slumber.

In the morning, an alarm jolts us awake.  We reach for the phone to check messages and emails. 

As with nearly every facet of our lives, our sleep cycle has been infiltrated by technology and modernity.

But many technological advances designed to help us fall and STAY asleep are actually inherently doing the opposite.

This is because our sleep clock is anciently programed into us, and it is more powerful than any technology. 


Our internal sleep clock is dictated by the all-powerful circadian rhythm.


Not only does it sound cool (Simply say the word “circadian” among a common group of people; they’ll think you’re enlightened.), this primal feature regulates your sleep and your metabolism too.

Check out what the circadian rhythm is and why it’s so important.  At the very least, it’s great material for the next time you feel like dropping knowledge at a dinner party.


What is the circadian rhythm?

Have you ever stayed up all night to see the sunrise?  You know that uneasy feeling you had when you saw that sun come up? 

Hey, maybe you’ve had a great night, but there’s a sense that there’s something not quite right in your world.

This is the voice of your circadian rhythm.

In basic language, the circadian rhythm consists of natural changes in the daily cycle of a living thing.  It’s a response to light and darkness.

The term comes from the Latin circa diem meaning “about a day”.  It was first observed in plants in the 18th century. 

Plants, humans, and almost all living things literally have this internal mechanism that tracks the Earth’s rotation.  We are evolutionarily programmed to fluctuate based on light and dark.

Pretty mind-blowing.

You and the flower in your garden both respond on a biological level to the rhythm of the Earth and the sun.


The Circadian Rhythm and Sleep

There is actually a circadian control center in our brain.  It corresponds directly with light and darkness. 

Ipso facto, human beings are actually genetically programmed to be waking at sunrise and hitting the hay at sunset.

But who do you know that’s actually following this schedule?

As we get older, we work less and our bodies long to return to the ancient circadian rhythm.  This is why you notice the elderly getting up earlier and going to bed earlier too.

A major reason for sleep disruption and the dire LACK of sleep among us today, on a biological level, is the compromise of this sacred rhythm. 

Consistent and quality sleep AT NIGHT is crucial to maintaining the circadian rhythm and vice versa. 


Sleep, circadian rhythm and metabolism

In addition to sleep, your circadian rhythm dictates your metabolic function.  It is THE link between sleep and metabolism.

This explains why there is a plethora of science and literature that links poor sleep habits with

  • high BMI (body mass index)
  • obesity
  • diabetes
  • weight loss difficulty

Sleep deprivation is shown to increase levels of our hunger hormone and depress the hormone that reduces appetite, even in just a single night.

Your body needs sleep to maintain the circadian rhythm which in turn maintains metabolic homeostasis.

In short, if you want to maintain a healthy weight, getting a good night’s sleep is JUST AS CRUCIAL as diet and exercise.


How can I maintain my circadian rhythm and consequently, my sleep and metabolism?

With over 30% of adults reporting less than six hours of sleep per night, it’s no wonder obesity rates are on the rise.

Follow these tips to keep your circadian clock in top shape:

  • Get exposure to natural light during the day. As much as you can.
  • Go with the flow of daylight: sleep when it’s dark and wake up with the light.
  • Maintain a low-fat diet with lots of plants.



Your inner circadian rhythm is pleading with you to get back to a more primal state of being.  And this goes beyond just sleeping.  Our bodies are begging us to get outside more often, to follow the natural patterns of the Earth like we were designed to do.

Answer the call.  Use that cell phone a little bit less.  Try turning it off at least half an hour before going to bed.  You’ll be surprised at how much easier it is to fall into a natural sleep pattern that way.

Nurturing your circadian clock, or rather restoring it to its normal state, will increase your mental well-being, your metabolic health, your immune function and your lifespan.

Take the time to take care of yourself.