Circadian Biology: Understanding and Optimizing Our Body's Natural Clock

Healthy Habits

Feb 2

Most of us have heard the term circadian rhythm. It is commonly known to be regulated by light and darkness in our environment, which makes us feel tired when it's time to go to bed and wakes us up when the sun rises. But there's more to it than that. Let's take a look into how we can manage it to optimize sleep (yes, please!), energy, productivity, and more.

What are Circadian Rhythms?

Circadian rhythms are defined as the natural processes that regulate various bodily functions over 24hours. These rhythms are driven by an internal "clock" that synchronizes with the environment, remarkably light and dark cycles. The term "circadian" comes from the Latin words "circa," meaning" around," and "diem," meaning "day."

Circadian rhythms are found in almost all living organisms, from bacteria to humans (some believe plants have them, too), and are at the core of our health and vitality. They regulate multiple functions in our body, including:

● Sleep

● Hormone production

● Metabolism

● Immune system function

How Do Circadian Rhythms Work in the Body?

Our body has a natural, unique clock that helps it know when it's time to sleep, wake up, eat, and do other essential things. But unlike any other clock we use, the circadian clock is designed to reset every single day depending on the time, information, and energy it receives from the solar (sun) cycle. How cool is that? This internal body clock is called the master clock. It's located in your brain, specifically in a small region called the suprachiasmatic nucleus (SCN). The master clock gets information from your eyes about whether it's light or dark outside.

Credit: NIGMS

The SCN communicates with all of the clocks in our body. These clocks ultimately help determine how we feel by balancing and regulating things like digestion, metabolism, and hormones. These body clocks can be found in tissues and organs such as the liver, heart, gut, pancreas, and muscles. The master clock and body clocks work together to keep our bodies running smoothly.

How Light Affects Circadian Biology

As mentioned above, when light enters the eyes, it travels to the suprachiasmatic nucleus (SCN), the part of the brain that serves as the body's master clock. All of our hormones and neurotransmitters are released at different levels and at different times of the day in response to our circadian signal. And this all starts with melatonin.

Melatonin, which we know as the sleep hormone and regulator, plays a much larger role than just sleep. It's more than just the hormone that helps the body know when to sleep and when to wake. It's the master hormone and neurotransmitter of circadian biology. Melatonin is made in our skin and in our eyes as a response to the red and infrared light we collect during the day.

Artificial light, such as the light from screens and other electronic devices, greatly affects our body's clock. Exposure to artificial light at night can disrupt the body's natural sleep-wake cycle and lead to problems with sleep and other bodily functions.

What Causes Circadian Mismatch?

Circadian mismatch occurs when the body's clock is out of sync with the natural light-dark cycle. This can happen due to various factors such as travel and shift work. But the largest mismatch occurs when our body is exposed to excessive article light at night (cell phones, TVs, computers, LED, and overhead lights).

Can you see where this is going? A circadian mismatch can lead to many of the chronic autoimmunity and metabolic conditions that we see affecting many people today. Not to mention circadian mismatch disrupts sleep, leading to fatigue, irritability, and difficulty concentrating. Sleep also affects the body's metabolism and hormone production, increasing the risk of certain diseases and disorders, such as obesity, diabetes, and heart disease. A circadian mismatch can also affect mental health and well-being, including mood disorders such as depression and anxiety and impaired cognitive function. Bottom line: We need sleep!

How to Optimize Your Circadian Rhythm

Here are a few simple and practical tips to optimize your body's clock and improve your unique level of health:

#1. Get sunlight during the day

Sunlight is one of the most important ways to synchronize the body's clock with the light-dark cycle. Get outside and in the sun multiple times per day. See the sunrise, take light breaks throughout the day, and see the sunset.

#2. Avoid screens and other sources of artificial light at night

Blue light emitted by screens and other electronic devices is entirely disruptive to the body. It inhibits sleep, increases cortisol and blood sugar, and is linked to many neurodegenerative diseases and cancer. Limit screen use after sundown, use blue-blocking glasses, and dim inside lights.

#3. Maintain a regular daily routine

Consistency is key to optimizing our circadian rhythm. Go to bed, wake up and eat at the same everyday, even on weekends.

#4. Eat Seasonally

Matching the sunlight that grows the food to the sunlight we are exposing our bodies to each day is crucial. Our bodies are designed to digest and process certain types of food(for example, carbs in the summer when UV light is strong). Eat the foods grown seasonally. How? Check out your local farmer's market or join a CSA to know what is grown in your area.

#5. Eat a hearty, protein-rich breakfast

Breakfast kicks off your metabolic function by supporting healthy cortisol levels and hormones and aligns with our body's clock. Aim for a big, protein-rich breakfast consumed within the first 60 minutes of waking. Grass-fed and pastured animal protein should be a staple. Bonus if you can eat outside!

To Wrap Up

The circadian rhythm is an amazing, natural process that regulates numerous functions in our body. It's driven by an internal clock in the brain and influenced by factors like light and our environment. Disruptions to the body's clock, known as a circadian mismatch, can negatively affect sleep, metabolism, and hormone production and lead to many debilitating, chronic conditions.

To optimize the body's clock and improve health, it's crucial to synchronize our body clock with the natural light-dark cycle, maintain a regular daily routine, eat seasonally, and enjoy a big, hearty breakfast. Getting our light environment correct and living an outdoor life will balance our internal clock, which will ultimately help us restore, thrive, and live our very best life.