This article was originally authored and published by Dr. Emily Parke.

After a long day behind the computer or a late night catching up on work under your kitchen light it seems to have you tossing and turning in bed later that night.

Not being able to go to sleep might not just be from a racing or worrying mind.

For the past 200,000 years, humans have evolved under the natural rise and set of the sun. Our bodies were literally programmed by the light and dark cycle.

With the introduction of incandescent lighting 150 years ago, humans threw a wrench in this natural cycle called your circadian rhythm. And with any dysfunctional system, this can lead to circadian rhythm disorders and other health issues.

But you have the power to change an altered circadian rhythm with a switch of a light bulb, turning down to night mode, or simply disconnecting.


What is Circadian Rhythm?

This specific rhythm in your body known as your circadian rhythm beats to the drum of the natural day-night light cycle. Not only have we humans evolved with this 24-hour sleep-wake cycle, but most organisms from billions of years ago have too.

Your circadian rhythm, which translates to circa “around” and diem “day”, applies to not only your sleep-wake cycle but to other cells and organs in your body as well.

Genes, cells, hormones, and organ systems in your body all beat to the circadian drum of a 24-hour period. These different molecular mechanisms involve certain genes, which express themselves differently in a feedback loop every 24 hours.

The main genes which participate in your circadian rhythm include:

  • BMAL1
  • PERIOD homologous 1, 2, and 3

These circadian rhythm regulators are powerfully influenced by the sunlight which enters directly through your optic nerves. Once the light enters it affects your “master clock”, which is located in your brain called the suprachiasmatic nucleus. This is made up of 20,000 neurons in a part of your brain called the hypothalamus.

Your circadian rhythm is truly in-sync with the world around you.


Why is Your Circadian Rhythm Important?

Not getting enough good quality sleep is a huge stress on your body.

Naturally waking during the day and sleeping at night, your sleep-wake cycle is just one example of a circadian rhythm. Other examples of circadian rhythms include:

  • Hormone secretion
  • Eating habits
  • Digestion
  • Body temperature

For example, when light is passed through your optic nerves this signals a reaction in your suprachiasmatic nucleus to regulate the release of the melatonin hormone. Secretion of melatonin helps make you drowsy when it’s time for bed, thus things such as shift work, artificial light, and jet lag can affect your sleep-wake cycle.


Circadian Rhythm Disorders

Your metabolic and endocrine systems are considered to be the most affected by a disrupted circadian rhythm. This is mainly because glucose is metabolized differently during the day versus night.

Liver metabolism is also another important function influenced by your circadian rhythm. The pathways affected by light-dark with your liver include:

  • Detoxification
  • Synthesis of hormones and nutrients
  • Activation of mitochondria
  • Production of energy

Your master circadian clock in your brain also has a connection to peripheral clocks in your body. Studies show a misalignment of the “ticking” of these two clocks have been shown to alter cell growth and promote inflammation and accelerate aging.

Irregular circadian rhythms have been linked to the following health conditions:

  • Sleep disorders
  • Cardiovascular disorder
  • Diabetes
  • Obesity
  • Depression
  • Bipolar disorder
  • Seasonal affective disorder
  • Cancer


Gut Microbiome and Circadian Rhythm

The verdict is out about your microbiome, the diverse community of microbes living in your gut – it has a strong influence on your overall health. It is estimated that there are up to 100 trillion bacteria in the gut microbiome. Certain diseases are strongly correlated to an unhealthy gut microbiome.

A change in the diversity of your gut bacteria or an imbalance of good bacteria to bad bacteria, known as dysbiosis, can lead to a laundry list of health conditions.

Common diagnoses that are affected by your gut bacteria include:

Research has shown the influence of an altered circadian rhythm has on your gut bacteria. Abnormal light-dark cycles can change the composition and homeostasis of your gut microbiome. Studies show how changes in bacterial composition, gene expression, and impaired intestinal integrity or permeability can lead to gut dysbiosis and other diseases.


Prevent Circadian Rhythm Disorders

The best way to avert circadian rhythm disorders is prevention!

Not only does light affect your circadian rhythm but temperature and eating are also taken as cues from your body to regulate your circadian rhythm cycle. This is why late-night eating can result in weight gain and obesity. I recommend avoiding eating at least 2 hours before bed.

Your gut bacteria run off the rhythm of your master clock. When you disrupt this master clock by eating when your body is supposed to be resting and rejuvenating it can’t digest properly, and thus is likely to lead to less deep sleep.

Night shift work, those traveling across different time zones consistently, and excessive use of artificial light are at higher risk. For those with jet-lag, short term use of the supplement melatonin can be especially helpful.

Artificial light is a big risk factor for all of us. Laptops, iPads, iPhones, TVs are all just an arms-reach away at any moment. This light throws off our circadian rhythm frequently, which is why it’s critically important to power down at a reasonable time. Ideally stopping screen time 1-2 hours before bed is ideal. In the evening, after the sun goes down, I recommend wearing blue blocking light glasses to help with sleep as well. You can also dim the lighting in your house after dark and/or switch to red tinted lighting, as the artificial blue lights are what tend to disturb our melatonin the most.

You’ve probably heard it before – disconnect from the digital world. This isn’t just because you should live your present life, but because it can actually help prevent circadian rhythm disorders. Have a consistent bedtime ritual that does not involve looking at screens, such as reading, listening to music, Epsom salt baths, deep breathing, or meditation has been proven to be extremely helpful.

If you are interested in hacking your sleep and learning more about your own body’s data, I recommend getting an Oura ring for accurate data sleep tracking, as well as other important information, such as your heart rate variability for example. I personally have one and found the data it provides to be tremendously useful getting more good quality sleep.

If you’re in the Phoenix, Scottsdale, Paradise Valley AZ area and need help at realigning your circadian rhythm request an appointment with Arizona Wellness Medicine or call (602) 892-4727.