Your Biological Clock and Sleep

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Sleep Awareness Week 2021, March 14-20, 2021

We all have a biological clock. This biological clock is sometimes referred to as your circadian rhythm or your sleep-wake cycle. In fact, there is a small “part” in your brain that controls all of this. It controls when your brain and other organs secrete chemical messengers, known as hormones, to other parts of your body to cause things to happen in your body. Even when this part is removed from the brain, it continues to function all on its own!

The reason that it is important to have a general understanding of how this biological clock works, is so that you can understand HOW to improve your sleep. If you understand some of the hormones involved, it may help you understand which natural supplements may help.

Here, you will learn more about two specific hormones (melatonin and cortisol) and a compound (adenosine) that are important for sleep. You will also learn how they play an important role in the functioning of your biological clock.

Melatonin

What Is Melatonin?

Melatonin is a hormone that is produced in your brain. It is actually synthesized from another hormone called serotonin. Melatonin production is stimulated by darkness, or when blue light is no longer entering your eyes. It is one hormone that contributes to feeling sleepy. It is also known to play a role in the reduction of aging in your brain and body, as well as to have cancer-fighting properties.

Melatonin production comes to a halt when blue light enters your eyes by way of daylight. As an aside, these blue wavelengths are what make the sky look blue when it scatters in the atmosphere. It’s also important to note that special “daylight lamps”, used by people with Seasonal Affective Disorder (SAD) or the “winter blues”, also provide the eyes with blue light required to elevate mood and reduce the fatigue associated with this disorder.

What Is Blue Light?

As you can see, blue light is what regulates your wake and sleep cycles. Blue light is emitted by natural sources such as the sun. It is also emitted by artificial sources such as televisions, computers, and phones, as well as fluorescent and LED lights.

It is therefore important to reduce blue light exposure in the evenings and while you sleep to get quality sleep. Our bodies were never designed to need blue light at nighttime. However, the use of artificial light sources has made it nearly impossible to avoid. Your body continues to think that it’s daytime and doesn’t produce adequate volumes of melatonin, thus confusing your body’s natural cycles.

This is a modern-day issue because years ago, lanterns and oil lamps were the norms. These items did not emit blue light. That is why you have your best sleep when camping, as long as you don’t use artificial lighting in the evenings. The setting sun and the natural light of the fire don’t interfere with your body’s biological clock. They actually encourage it to do what it’s supposed to do – release melatonin required for sleep;

Cortisol

What Is Cortisol?

This is another important hormone that affects your sleep. Under normal, healthy conditions, cortisol levels should rise in the mornings, and decrease in the evenings. In contrast, the sleep hormone, melatonin, is supposed to rise in the evenings when darkness prevails. It then decreases in the mornings for waking. So as melatonin levels decrease, your cortisol levels pick up. Both hormones are similar though, in that they both work on a 24-hour cycle in your body, supporting your body’s biological clock.

Cortisol is known as one of the “fight or flight stress hormones.” It is released by your adrenal glands in your body. When released, cortisol increases your blood sugar levels, so that your muscles and brain get the energy needed to act. It helps wake you up and keeps you alert during the daytime. It is typically highest at 8 a.m., and lowest between the hours of midnight and 4 a.m.

Impact of Too Much Cortisol

Unfortunately, too much cortisol is not a good thing either, especially when your cortisol levels remain high throughout the evening. This occurs when you are experiencing emotional or physical (i.e. sickness) stress. Even having an upsetting conversation, learning exciting news, or watching a thrilling television show in the evening can increase your cortisol levels. These elevated cortisol levels can then keep you from falling asleep and prevent you from having a restful sleep.

Unfortunately, if your adrenal glands continue to secrete cortisol, as during periods of prolonged stress, eventually they burn out. This is what is referred to as “adrenal fatigue”, and normal surges of cortisol in the morning no longer occur. In fact, if your adrenal glands aren’t producing enough cortisol, your blood sugar levels aren’t going to be high enough at night. Your sleep will suffer as you wake up earlier from the brain signaling its hunger. To complicate matters, if you don’t get enough sleep one night, your cortisol levels will be elevated the next night.

As you can see, your body’s systems and hormones are all inter-related. What happens to one, affects another, and together, they impact the quality and quantity of your sleep.

Adenosine

What Is Adenosine?

This is another chemical naturally found in your body. Without getting into the complex chemistry, all you need to know is that adenosine builds up each hour that you are awake causing you to become sleepy. Adenosine is a byproduct of your cells working and using energy in your body. It works in conjunction with melatonin, which is released in response to darkness. Adenosine breaks down when you sleep.

When you exert more energy through physical exercise and labor, your adenosine levels may increase. This causes you to feel sleepier at night. That is why you feel very sleepy after a long day of activity compared to when you are less active.