Circadian rhythms: How to reset your body clock

BY Karen Heath

17th Jan 2023 Wellbeing

Circadian rhythms: How to reset your body clock
Getting to know your natural circadian rhythms will do wonders for your health. Here's how to reset your body clock for better sleep, mood and wellbeing
Circadian rhythms are what most of us call our “body clock”. It’s our 24-hour sleep-wake cycle or our body’s natural internal timing devices that tell us, among other things, when to go to sleep, when to wake up, and when to eat.
It makes sure our body’s processes are optimised at various points during a 24-hour period and is largely set by signals our brain receives from our environment, such as light and darkness.
However, according to consultant neurologist and sleep disorders specialist, Dr Oliver Bernath, our personal circadian rhythms are also largely denoted by our individual genetic chronotype—that is our body’s natural sleep schedule.
If you constantly struggle to get up early in the morning or start nodding off at 9pm, it may well not be your fault. “Our individual chronotype—being a morning type, or evening type, lark or night owl—often gets ignored or misunderstood,” says Dr Bernath.
"Living with your chronotype rather than against it can be life-transforming"
He suggests that we should just go with our natural chronotype and not strive to change it. “Performance levels on pretty much anything you want to measure will vary over the 24-hour period and peak performance comes at different times for larks and owls.”
Knowing whether we’re larks or owls is important as Dr Bernath says, “living with your chronotype rather than against it can be life-transforming.”
When it’s disrupted it can lead to all sort of issues, including problems with memory, sleep, digestion, weight gain and even mental health conditions.
Unfortunately, it’s only too easy to disrupt your circadian rhythm with our modern lifestyle and this includes:
  • Jet lag—from travel that crosses one or more times zones
  • Late nights or very early wake times
  • Stress
  • Working night shifts
  • Poor sleep habits—that is not having a regular sleep schedule
  • Using screens late at night
  • Age—as we age, we may find we wake up very early and sleep during the day
What can we do to try to ensure we keep our circadian rhythms in check? The following are the key lifestyle factors to address:

Manage your light exposure

Open your curtains first thing to get the morning sunlight's full effects on your circadian rhythm
Light is the most powerful factor in aligning your circadian rhythm. Daylight exposure helps our brains to sync with our internal body clock, signalling to our brain to stay awake and active.
We are especially sensitive to sunlight during the first hour after waking, so open the curtains or go outside.
Likewise, avoiding bright light in the evening can also help align our body clocks.
"We are especially sensitive to sunlight during the first hour after waking, so open the curtains or go outside"
Being exposed to harsh, artificial lighting at night, particularly from fluorescent bulbs or the light from our mobile phones, tablets or computers (which have a bluer, more disruptive wavelength than other lighting) is particularly disruptive to sleep and should be avoided before bed.
Cells in the eyes that respond to light are particularly sensitive to this blue light and signal to your brain that you should be alert rather than sleepy.
Seasonal Affective Disorder (SAD) is a recognised medical condition where some people feel down and depressed in the winter months. Researchers believe this is due to the changes in circadian rhythms, as a result of the shorter daylight hours in winter.


Set a consistent sleep schedule and stick to it. At night time, our brains produce the hormone, melatonin, to help us feel sleepy and help us sleep throughout the night.
Keeping the bedroom cool, therefore bringing down our core temperature, helps to signal to our body that it’s time to sleep.


Be careful not to exercise too close to your bedtime, as it can reduce your quality of sleep
We’ve heard it before but making time for aerobic exercise—that is any exercise that increases our heart rate for 20 minutes or more—is good for our health and will help with better quality sleep.
If possible, it’s better to exercise earlier in the day and to avoid vigorous activity in the last few hours before going to bed, as this can sometimes be stimulating.

Eat at regular times

Eating meals is our body’s signal to boost our metabolism. Eating erratically can confuse these signals and set our body clocks off course, as our digestive systems have their own circadian rhythm.
After waking our body releases hormones that make us feel hungry and also help to break down and digest food.
"Eating erratically can set our body clocks off course, as our digestive systems have their own circadian rhythm"
If we eat too early or too late in the day there are fewer of these hormones available and the body has a tougher time regulating blood sugar after eating. This is why, over time, this can potentially lead to obesity and even diabetes.

Avoid coffee in the evening

Coffee pushes back the release of melatonin, and our body won’t think it’s time to sleep until later and will keep you alert.
So, for ultimate health and good sleep in 2023, it’s worth being aware of our circadian rhythms and taking the above measures to keep them on track.
Find out more on circadian rhythm with 'The Circadian code' on Amazon.
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