Have you noticed how you feel really tired or wide awake at the same time every day?

Some people might feel energised and ready to go at 11am, only for the post-lunch slump to hit around 3pm. For others, it’s the other way around.

Why is this? Well it all comes down to something called circadian rhythm.

16th March 2018 was World Sleep Day, and this year it’s all about circadian rhythm and why it’s important to sleep quality and a healthy lifestyle.

Circadian rhythm definition

Circadian rhythms are found in most living things and are a series of daily behaviours that follow a cycle. They respond to external factors in your own environment – for example darkness and light - which why most people go to sleep at night and are awake through the day.

As well as affecting when you go to sleep and wake-up, circadian rhythms also relate to your daily body temperature, eating habits and even your bowel movements.

Circadian rhythm and sleep

Your circadian rhythm is more likely to be out of sync if you’re not getting enough sleep, or enough quality sleep.

Your hypothalamus, which a part of your brain, is responsible for how your circadian rhythm operates. The hypothalamus is linked to your nervous system and sends signals to let you know when it’s time to feel tired or awake.

Other external factors can influence your hypothalamus too, such as darkness and light, which is why you’re more likely to feel tired at night – the darkness is telling your hypothalamus that it’s an optimum time for sleep.

For those who work on night shifts, this can be very disturbing and may knock their circadian rhythm out of kilter – especially if they swift between morning and night shifts.

Irregular circadian rhythms can have a serious impact on someone’s health, and have been linked to sleep disorders, obesity and depression.

How can I maintain a healthy sleep cycle?

Unless you suffer from a circadian rhythm disorder, it mainly comes down to: routine, routine, routine. Having a regular bedtime helps train your body to understand when you’re going to going to sleep or waking up.

That’s why things that disturb your usual routine, such as jet lag or alcohol consumption, will momentarily disturb your circadian rhythm, leaving you to feel lethargic the next day and mentally and physically impaired.

When going to bed, make sure you create an environment conducive to good quality sleep.

Here are a few tips to get you started:

  1. Make your bedroom and “no tech zone”:  the blue light that emits from your phone has been known to disrupt sleeping patterns. Try and stop that midnight browsing on Facebook, and free your bedroom of all that disruptive tech.

  2. Be consistent: try and aim to bed tucked-up in bed for 10/10.30pm. This will help create a routine and regulate your circadian rhythm. Soon enough, your body will start anticipating when you’re about to fall asleep.

  3. Lay off the caffeine: most of us are guilty of relying on caffeine to keep us going through the day. However, caffeine really isn’t great for inducing sleep and it can take up to 10 hours for caffeine to totally leave your system. With that in mind, try to refrain from that post-lunch coffee and try herbal or fruit tea instead. You’ll be thankful for it when it comes to bedtime. 

  4. Invest in quality sleep: if you’re sleeping on a tired old mattress full of loose springs night after night, your sleep will inevitably suffer. A new, quality mattress will improve your sleep and help you recuperate properly. Think of it as a long-term investment in your own health.

For someone suffering from a circadian rhythm sleep disorder, the solution may not be as simple. There are a number of disorders associated with circadian rhythm and we always advise consulting your doctor for professional support.

These disorders can include:

Advanced sleep-wake phase: where people fall asleep and wake-up hours before the majority of people do.

Delayed sleep-wake phase: when optimum sleep-times are delayed by two hours or more than the person desires, or is socially acceptable.

Irregular sleep-wake pattern: no clear sleep-wake pattern is apparent and sufferers nap irregularly throughout the day to compensate for these inconsistencies.

Non-24-hour sleep-wake rhythm: sleep and wake-up times shift later and later every night, causing disorder in the sufferer’s life.

Jet lag: when you travel to another country your body needs to adjust to different time zones. This affects your circadian rhythm as your body is anticipating sleep at different times.

Shift work: irregular or late working-hours can disturb someone’s natural sleep-wake cycle or they may find issues readjusting to different sleep-wake cycles dictated by their shift patterns.

There are a number of treatments for circadian rhythm sleep disorders, including behavioural therapy, dark therapy, various medications and sleep phase chronotherapy.