How much attention do you pay to your circadian rhythm? Do you ensure that you are in sync so that you can sleep well regularly? Do you prioritise sleep to support your physical and mental health?
In this blog, Dr Lindsay Browning explores the topic of sleep and wellbeing and looks at how sleeping in tune with our circadian rhythm affects both our physical and mental health.
Sleep and Wellbeing – maintaining a regular circadian rhythm
Regular sleep which is good quality is important for our health and wellbeing.
Maintaining a good sleep schedule starts with maintaining our regular circadian rhythm. This is our internal 24-hour clock and tells our body what to do at certain times of the day.
It influences many aspects of our health and wellbeing, including core body temperature, when we feel sleepy or awake, food digestion, our immune system and stress hormones (such as cortisol).
When we rapidly change bedtime and wake times, our circadian rhythm may not catch up with the change, leading to things like producing hormones (such as the sleep hormone melatonin) at the wrong time.
When people move their circadian rhythm by significantly changing bedtime and wake times during the week (such as shift workers), they tend to have a higher risk of mood disorders.
Disruptions to your circadian rhythm
Time zone changes
A common way that our circadian rhythm is disrupted is when it is subject to a time zone change. This could be a small adjustment, such as the clocks going back or forwards. Or it could be a large disruption such as travelling abroad to somewhere like Australia or the USA, where there is a significant time difference. When our bodies experience this it is common that we want to sleep when it is daytime and want to be awake when it is nighttime. The horrible feeling of trying to readjust our circadian rhythm to suit ‘night and day’ where we have travelled too is what we commonly call ‘jetlag’
One of the best ways we can change our circadian rhythm is though bright light exposure. When we are exposed to lots of bright light, our body knows it’s daytime and our circadian rhythm helps to keep us feeling awake and alert. When there is darkness, our circadian rhythm knows that it is night time and produces melatonin, our sleep hormone, to help us fall asleep.
Light can be used to manipulate and move our circadian rhythm. For example, bright light exposure soon after waking can help us to feel more alert and wake up more easily. Morning light can help people to fall asleep earlier at bedtime, and then to wake up earlier in the morning feeling less groggy. Conversely, bright light right before bed will disrupt sleep, because it will wake you up, rather than help you produce melatonin and fall asleep.
The impact of regularly disrupting your circadian rhythm
Sleep, gut health and weight gain
The circadian rhythm affects gut motility, which means how quickly we digest food.
A recent study from Kings College London found that people who went to bed at different times during the working week versus the weekend (changing them by 90 minutes or more) had more harmful gut bacteria (microbes) compared to those who kept more consistent bedtime and wake times seven days per week.
The microbes they found were associated with poor diet quality and are indicators of obesity and poor heart health. In addition, other studies have shown that people who move their bedtime and wake times during the week (such as shift workers) tend to have trouble falling asleep, have a higher risk of certain types of cancers, obesity and diabetes. The circadian rhythm tends to affect insulin production and sensitivity.
Other physical and mental health impacts
Regular sleep is part of maintaining a good circadian rhythm. If you regularly get between 7-9 hours’ sleep per night then you are more likely to boost your immune system. There is also evidence of long term reductions in risks of cancer, heart disease and Alzheimer’s.
As for mental health, regular sleep can also mean a reduced chance of depression and anxiety.
How can we help maintain a strong circadian rhythm
Now we know what our circadian rhythm is and why it is important for our gut health, as well as other physical and mental health advantages, here are some three simple tips to maintain a strong circadian rhythm:
- Have regular bedtime and sleep times – throughout the whole week
- Don’t eat food when your body thinks you should still be asleep – so avoid nighttime snacks.
- Get lots of bright (natural) light in the daytime (when you want to be awake)
- Avoid bright lights (including blue light, from phones and devices) in the evenings and at bedtime (when you want to feel sleepy).
Sleep and wellbeing – prioritise maintenance of your circadian rhythm.
Sleep is important! It is something I am very passionate about. Maintaining a strong circadian rhythm is part of this too. Look after yourself and your wellbeing by getting regular sleep. Ideally, it should be both good quality, as well as the right quantity. Quantity of sleep also means that you are getting enough of each sleep stage. Learn more about why this is important for health and wellbeing too: