Circadian Rhythm 101: Unraveling the Science Behind Your Body's Internal Clock

Have you ever considered the driving forces behind your daily habits, like waking up just before your alarm, or feeling the need for an afternoon cup of coffee? Or wondered how your body knows when it's time to sleep and when it's time to wake up? Though an alarm clock may aid in making sure you awake at the right time, there's another, more subtle, timekeeper at play – our circadian rhythm.

Wondering “What is circadian rhythm?” don’t worry, people frequently scratch their heads when they hear the term as well as others like "biological clock" and "sleep rhythm", you’re not alone!

In simple terms, the circadian rhythm is a 24-hour clock dictating millions of invisible metabolic processes that keep your body alive. These include digestive rhythms, fat burning and fat storage, sleeping patterns, and much more. This biological rhythm is run by clock genes that signal when each process should take place. And guess what? The way you treat your body can have a big impact on your circadian rhythm, and thus on your overall health and wellness.

Curious to learn more? Let’s uncover the secrets of our body's master timekeeper and how to maintain a healthy circadian rhythm. Ready? Let's dive in.

How the Circadian Rhythm works?

Circadian rhythm works by making sure that the body’s processes are optimized at different times during a 24-hour period. And fun fact, the word circadian is derived from the Latin phrase “circa diem” which roughly translates to “around a day.” It’s all starting to make sense, right?

Circadian rhythms exist in all types of organisms. For example, they help flowers open and close at the right time and keep nocturnal animals from leaving their shelter during the daytime when they would be exposed to more predators. In people, circadian rhythms coordinate mental and physical systems throughout the body.

Indeed, the circadian rhythm is made up of a set of clocks and a central “master clock”, called the suprachiasmatic nucleus (SCN). Nestled in the hypothalamus, this central clock oversees stress, reproduction, and growth hormones, while also indirectly influencing sleep hormones. For example, after a meal it instructs your digestive systems to produce certain proteins; when the sun sets it starts your melatonin release; before you awake it kicks off your cortisol levels: once you’re awake it stops your melatonin release. In short, if your body were an orchestra, the “master clock” would be its conductor. 

It is composed of roughly 20,000 cells, situated just above the optic nerve junction. These cells also respond to light exposure, notably the melanopsin cells in the retina, which respond to natural daylight as well as artificial light such as blue light from phone and TV screens.

What happens when Circadian Rhythms is Off?

When the circadian rhythm goes offbeat, it's like the body's systems are dancing out of tune. Circadian misalignment occurs when your internal circadian rhythm finds itself out of sync with the biological night. This can occur with jet-lag, a crazy night out, working late hours etc. Your first indicator will be that your sleep/wake cycle seems “off”. You may have difficulty falling asleep, experience waking up during the night, or find it challenging to sleep as long as desired in the morning. The overall duration of your sleep may be reduced, and the nature of your sleep may become shallower, fragmented, and lower-quality.

If your circadian rhythm is misaligned for longer periods of time it can lead to more serious consequences for your health. One study showed participants with impaired circadian function had higher blood glucose, insulin levels, and blood pressure—indicators of metabolic and cardiovascular disease. Night shift workers also face higher risks of obesity, type II diabetes, hypertension, coronary heart disease, and ischemic stroke. Research also keeps unveiling circadian rhythm connections to mental health, including psychiatric illnesses like depression, bipolar disorder, and neurodegenerative diseases like dementia. So, let's all give a shout-out to our internal clock for keeping everything running smoothly and find out how we can help it continue its great job.

How to maintain a healthy Circadian Rhythm

We all understand that we can’t entirely control out circadian rhythm – however, don’t be scared as there are some healthy sleep tips easy to apply to keep your biological clock in check:

1. The circadian rhythm is not a caffeine fan
   Coffee lovers, be ready and take some notes! Stimulants like caffeine can keep you alert, disrupting the sleep-wake balance. Of course, everyone is different, but if you’re having trouble sleeping, you might need to reconsider caffeine after noon.
2. Let there be light!
   Throw open those curtains and let the sunshine in! Your brain needs a good morning boost to kickstart your day, and bright light is just the thing it needs. Don’t forget to expose yourself to bright light during the day – either sunlight or artificial light. Neuroscientist Andrew Huberman himself has a morning routine that includes prioritizing natural sunlight exposure as soon he wakes up. He suggests spending at least 2-10 minutes outside, ideally without sunglasses, to allow the eyes to receive direct sunlight to regulate circadian rhythms, improving sleep, mood, and cognitive function throughout the day.

3. Work-out in the day. Sleep hard at night.
   What makes it better is combining your light exposure with daily exercise. Think morning run, afternoon walks, cycling to work. In fact, a daytime activity can support your internal clock and make it easier for you to fall asleep at night.

Let's remember, our internal clock is super important for sleep cycles and overall wellbeing. Manage your biological rhythms for consistent, high-quality rest, and you'll be ready to rule the world!