The circadian rhythm is a roughly 24-hour cycle of behaviors, processes and changes in our body that repeats everyday. You can think of it as an internal clock that responds to environmental factors like light and temperature. 

Sleep is the most prominent part of the circadian rhythm. In fact, a lot of processes in the body, from temperature control to hormone regulation, are dedicated to making sure you get sleepy in the evening and sleep well. 

How a Disordered Circadian Rhythm Affects Sleep

Circadian rhythm plays a major role in your sleep quality. So if your internal clock is not running right, it affects how well you sleep. 

This is why jet lag causes such a mess to your sleep. Flying across time zones confuses your internal clock and throws your circadian rhythm out of sync. You feel sleepy when you shouldn’t and stay alert when you should be asleep. 

Other factors that affect your circadian rhythm include stress, lack of physical activity, diet, and exposure to temperature and light. These body cues are called zeitgebers.

When your circadian rhythm goes out of sink, it affects your ability to fall asleep at the right time and enjoy deep sleep. It can lead to sleeping too late (sleep onset insomnia), difficulty staying asleep (sleep maintenance insomnia), daytime sleepiness and sleep deprivation. 

Poor sleep is a very serious problem. For one, it affects how you carry out everyday tasks like driving, studying and work. In many cases, sleep deprivation is hazardous. 

Secondly, poor sleep affects almost every aspect of your health including physical and cognitive health. So fixing your disordered circadian rhythm is literally a matter of life and death.  

Good to know: An out of sync circadian rhythm is not just bad for your sleep; it can also cause hormonal problems, abnormal heart rate and blood pressure, and increased risk of diseases like cancer and heart disease. 

5 Ways to Fix Your Circadian Rhythm 

1. Establish a Regular Sleep Routine 

The easiest way to mess up with your circadian rhythm is having an unpredictable bedtime. This is especially common in people who sleep late. If some days you sleep at 11pm and on others you stay up past midnight, your circadian rhythm never gets a chance to get into a predictable cycle. 

Having a regular bedtime routine stabilizes your internal clock. You’ll find yourself easily getting sleepy around the same time everyday and waking up at the same time as well. 

You’ll also find you are more alert during the day, not just because you are getting better sleep, but also because your circadian rhythm is functioning normally. 

2. Get In Some Exercise During The Day 

The circadian rhythm is not one giant clock running everything in the body. Rather, it is a combination of individual cell clocks. So your muscles have separate clocks from your heart clocks. All these clocks need to sync for a smooth running circadian rhythm.

Exercise is one of the cues that helps your body synchronize all these clocks. Not only does this help you sleep better, it also improves metabolism, blood glucose control and other processes in which muscles are involved. 

In addition, exercising increases sleep drive by making you tired. This makes it easier to sleep at night and gives you deeper sleep. 

Tip: Some research has found that afternoon exercise is the best for circadian rhythm, but muscle clocks can also adapt to your preferred workout time. So don't worry too much when you work out. But don’t do it too close to bedtime. It throws the circadian rhythm out of sync. 

3. Spend Time Outdoors During the Day 

Light is a hugely important zeitgeber (cue) for the circadian rhythm. Exposure to light during the day keeps you alert and energetic. Lower light levels in the evening signal to your body to start turning down for the night. 

To help your circadian clock run smoothly, spend time outdoors during the day. Being outdoors is also great for reducing stress and anxiety, which improves sleep quality. 

4. Maintain Regular Meal Times

There is a good amount of research showing that eating large meals late at night is more likely to cause weight gain and increase risk of metabolic disorders like diabetes. 

This could be because of the gut clock (remember each organ has its own clocks). Because of the gut clock, digestion is more efficient earlier in the day. Late night digestion is inefficient and leads to poorer metabolism, worse glucose control and appetite hormones may also not work properly. 

Eating at regular times keeps your circadian clock in sync, which improves other body processes including sleep. Be especially careful with evening meals. A light and early dinner is best. It also keeps a full belly from disrupting your sleep (because of gas, reflux, discomfort and other issues).  

5. Avoid Late Afternoon Naps

Napping during the day is fine, as long as it’s a short nap early in the afternoon. Late afternoon naps, on the other hand, confuses your circadian rhythm. This in turn messes up with your sleep at night is likely to lead to sleep deprivation the next day. 

6. Reduce Exposure to Light During Bedtime

We are still not sure whether blue light from screens is to blame for the chronic undersleeping that’s plaguing so many people today. What we do know is that light exposure is an important cue for the circadian clock. 

It’s one of the reasons we sleep best in the dark. So in the evening, start reducing how much light you are exposed to. This includes putting down screens, turning off some lights and dimming lights. It sends the right signals to the circadian rhythm and helps boost the production of melatonin, a sleep hormone.

7. Avoid Caffeine and Other Sleep-disruptive Substances Close to Bedtime

Finally, watch out for foods and drinks that disrupt circadian rhythm. For instance, coffee in the evening resets the circadian clock, delaying how soon you sleep. But in the morning, coffee helps jumpstart your circadian clock and makes you more alert. 

As for alcohol, researchers have found that it reduces the body’s sensitivity to circadian clock cues like light and temperature. Reduce how much you drink and avoid drinking too close to bedtime. 

Smoking also messes with your internal clock, resulting in poor sleep and health problems.