What is a circadian rhythm and how does it affect sleep?

September 21, 2020 5 mins read
What is a circadian rhythm and how does it affect sleep?

Did you know that we have a built-in 24-hour clock called a circadian rhythm? You’ve probably noticed that around the same time every day you start to feel sleepy, while at other times you’re full of energy. This is your circadian rhythm operating in the background of your brain and body, guiding your sleep and wake cycles.

Your circadian rhythm is controlled by your biological clock. If not in sync, it can result in irregular rhythms, which have been linked to many chronic health conditions, such as sleep disorders, obesity, diabetes and depression. Keeping your body clock in sync is important for your overall health and wellbeing, so let’s find out how your circadian rhythm works and how to manage your sleep patterns.

What is a circadian rhythm?

Think of a circadian rhythm as a kind of built-in smart alarm clock which guides the sleep and wake cycles of all living beings, including plants, animals, fungi and photosynthesis bacteria. This rhythm is generated within us and is fine-tuned to sync with sunlight, determining our sleep patterns. Even our brainwaves, hormone production, cell generation and other biological functions are linked to this daily cycle.

How does a circadian rhythm affect sleep?

Your circadian rhythm determines your sleeping patterns by controlling the production of melatonin, a hormone that makes you sleepy. When you are in bright light, you produce very little melatonin. When there is less light, like at night, your body clock tells the brain to make more melatonin, making you feel drowsy and preparing you for sleep.

When your body clock takes cues from the environment, it’s figuring out when it’s good for you to eat, when you should be more active and when it’s time for sleep. If your sleep-wake cycle is not in tune with your environment, it can throw your body’s schedule out of whack, causing sleep disruptions.

These disruptions in your sleep patterns can be temporary and are most often caused by poor sleep hygiene, a stressful job and travel (jet lag being the easiest way to throw your body clock out of sync). A constantly disrupted circadian rhythm can lead to more serious health consequences, such as heart disease, metabolism issues and reproduction problems.

If you feel like your circadian rhythm is a little off-kilter, look out for symptoms such as daytime sleepiness, insomnia, decreased alertness and poor memory retention. These could signal that you need to re-adjust your sleeping patterns.

What causes the rhythm to get out of sync?

Natural light key to a healthy rhythm. However, our everyday lives, cased in artificial light, throw our natural circadian rhythm off balance. As we spend less time outdoors, more time behind desks and glued to our phones, our brains find it difficult to decipher day from night, which disturbs our circadian rhythm and harms our melatonin production. The natural signal (the wax and wane of light) that tells our body clock when to react, becomes confused.

5 ways to fix your circadian rhythm

Any unnatural disruptions to your usual sleep cycle will have some effect on your circadian rhythm, so paying attention to when you go to bed and how you sleep is important. Are you allowing your body to follow the natural light cycle to keep your rhythm? And how can you reset your internal body clock and get your body to function optimally?

Here are some ways you can help bring your natural sleep cycle back into sync:

1. Get natural light exposure during the day

Reset your sleep cycle by following the earth’s natural cues. Ensure that you are exposing yourself to natural sunlight and bright light in the morning and throughout the day. As the evening sets in, start dimming the lights to prompt your body into producing melatonin to signal that it’s time for bed.

2. Have a regular meal schedule

Did you know that digestion and metabolism also play a role in wakefulness and sleepiness? The time you eat actually helps reset your sleep clock. Sticking to regular eating times can help support consistent circadian rhythms. Try eating dinner a few hours before bed, (leaving 12 hours between breakfast and dinner), followed by breakfast shortly after waking up.

3. Avoid napping

If your sleep schedule is out of order, avoid naps at all costs. Whilst you’re getting your body clock back to normal, stick to a natural sleep pattern. Any napping will make it difficult to sleep later on. However, if you absolutely must take an afternoon snooze, ensure it’s before 3 pm and no more than 30 minutes long to try and prevent any nighttime disruptions.

4. Limit screen time

The blue light emitted from electronic devices can trick your body into thinking it’s daytime, even when it’s dark outside. The longer you expose yourself to this light in the evening, the longer melatonin production is delayed, and the longer it will take you to fall asleep.

5. Have a bedtime schedule

Fixing your sleeping patterns starts with creating a sleep schedule. Set a bedtime and wake-up time that fits your lifestyle, but ensure you get at least 7 or 8 hours of sleep every night. By following a regular routine, your internal clock will develop one too, and over time, you’ll be able to fall asleep and wake up on autopilot.

Why is it important?

At the end of the day, all we want is to be able to sleep soundly, wake up in the right sleep phase and maximise our energy levels for the day ahead. So let’s allow the light to guide us. Keeping a consistent sleep-wake schedule and allowing the earth cues to guide your circadian rhythm can steer you clear of poor sleep and other problems.