WHAT IS YOUR CIRCADIAN RHYTHM AND HOW DOES IT AFFECT YOUR SLEEP?

Have you ever found yourself scrolling on your phone late at night, trying to understand why you can’t sleep? The answer could be staring you right in the face. Our exposure to different kinds of light significantly affects our circadian rhythms – but what are they? And what can cause a circadian rhythm sleep disorder? We shine a light on how your sleep habits influence your entire day.

CIRCADIAN RHYTHM DEFINITION

Circadian rhythms exist in most living things, from large animals to tiny microbes. If you’ve ever wondered how a plant knows to open its flowers with the sun each morning, this is their circadian rhythm. It’s a natural process primarily governed by light (and, in turn, darkness) but is all down to our internal clock.

In Latin, circadian means “around or approximately” (circa) “a day” (diem), which illustrates how these rhythms roughly follow a 24-hour cycle. In humans, our circadian rhythms are the physical, mental, and behavioral changes that occur at different times of the day. They influence different processes, such as:

• Sleep-wake cycles.
• Hunger and digestion.
• Hormones.
• Body temperature.

When people talk about their circadian rhythms, they are usually referring to their sleep and any disruptions they may experience to their rest and recovery. But in turn, this has a big impact on their alertness and energy levels throughout the day.

It’s important to understand how your 24-hour cycle flows so you understand your individual rhythm. Whether it’s being able to focus on work, feeling great going for a run, or knowing when is the best time to wind down, understanding your circadian clock will help you get the most out of every day.

WHAT REGULATES YOUR CIRCADIAN RHYTHMS?

Nearly every tissue and organ in your body contain a biological clock, which regulates your daily cycle of circadian rhythms. These clocks are, in fact, molecules made of protein that can communicate with the cells in your body.

Nearly every tissue and organ in your body contain a biological clock, which regulates your daily cycle of circadian rhythms

A master circadian clock in your brain keeps all of these biological clocks in sync. It is called your suprachiasmatic nucleus (SCN), which consists of 20,000 nerve cells in your hypothalamus, the brain’s control center.

Your SCN receives direct input from your eyes, which relay information via the optic nerve about the light in your environment. This data then informs your SCN’s production of melatonin, the hormone that makes you sleepy. So, when it’s night, or you are immersed in a dark environment, your SCN tells your brain to create more melatonin to make you drowsy. If you’ve ever had a nap in a cinema, it was probably because of your SCN.

CIRCADIAN RHYTHM SLEEP DISORDERS

A circadian rhythm sleep disorder occurs when your sleep-wake cycle is out of sync with your environment. This inconsistency could result in one of the following disruptions:

• You struggle to fall asleep at night.
• You frequently wake up during the night.
• You wake up during the night and can’t go back to sleep.