What is Circadian Rhythm, Anyway?

What is Circadian Rhythm, Anyway?

If you’ve ever woken up on time without an alarm, you can thank your body clock for that. For most of us, our bodies work synchronously to our environment–especially light. We wake in the morning, and we sleep at night. When the time changes, such as for daylight savings or due to travel, adaptation can be difficult at first but eventually, we resynchronize. 

Our bodies exist on their own schedule, independent of external time, but nonetheless affected by it. We train our bodies to adapt to external time as to make our lives easier. But understanding our circadian rhythm, or our internal clock, can be hugely beneficial to understanding the energy we have throughout the day and the quality of sleep we’re getting each night. 


Where it all started
The human body’s natural cycle has been studied and treated for centuries, dating back to the start of traditional Chinese medicine in the early 13th century. But the process we understand today as circadian rhythm was coined by two German zoologists, Hans Kalmus and Erwin Bünning, in 1935, who studied natural sleeping and eating patterns in fruit flies. They found that all living things–bugs, plants, humans, etc.–have their own 24-hour cycles in which body functions are carried out. 

In 2017, three other scientists, Jeffrey C. Hall, Michael Rosbash, and Michael W. Young won the Nobel Prize for their research of the genetic make-up that controls the body’s “master clock” in the brain. They found that protein builds up in cells overnight and breaks down during the day–a cyclic process that affects when and how we sleep, the hormones our bodies produce, how our brains function, and more. 

What it means for us
Examples of circadian cycles include hibernation, metabolism, menstruation, and body temperature, and perhaps the most popular: the sleep-wake cycle. Our bodies work hard to maintain their natural internal rhythm despite our external environment. However, being conscious of our environment is one way to support our circadian clocks in a healthy and productive way. The less we disrupt our circadian rhythm, the better we sleep, think, digest, and feel. 

How we maintain good rhythm
We’ve all experienced how changes in time and place affect our sleep. So, mindfulness and consistency are key to maintaining our internal clocks. First, it will be helpful to be mindful of the way our environments affect our minds and bodies. Then, we should try our best to be consistent in supporting the places and routines where we feel our best.  

One proven way to do this is to be proactive about our daylight intake in order to support our sleep-wake cycle. Daylight sends a message to our brains to awaken and energize the body. So, the majority of our active time and alertness in a 24-hour period is during daylight. Then, our bodies get the best quality of sleep in dark, cool, quiet places. This is because dark environments trigger our bodies to produce Melatonin, the hormone that helps us sleep, among other things. Sleep aids like silk eyemasks, bedding that helps maintain cool temperatures, or white noise machines, are all ways to promote a circadian-friendly sleep. 

Other factors like exercise, diet, and mental health, play a role in our bodies hormone production and the overall maintenance of a healthy and consistent circadian rhythm. Keeping to your body’s natural schedule, per se, and doing what you can to support that schedule, is one of the best forms of self care there is. 

The Sleep Foundation
National Institute of General Medicine Sciences
The Centers for Disease Control and Prevention

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