Your circadian rhythm explained

The body clock

Our body’s 24-hour sleep/wake cycle happens like clockwork: we wake in the morning, go to bed in the evening, and our levels of peak alertness and sleepiness tend to fluctuate at similar times every day. 

But what is it that’s driving this powerful inner clock? Scientists call it our circadian rhythm  or ‘body clock’, which is essentially the natural cycle of physical, mental and behavioural changes that the body goes through in a 24-hour cycle.

What is a circadian rhythm?

Circadian rhythms  are found in most living things , from tiny microbes, fungi and algae to insects, plants, animals and humans. 

In humans, circadian rhythms influence the sleep-wake cycle. They also affect other physiological processes  such as nervous system activity, hormone production, blood pressure, appetite, digestion and body temperature. Even our mood and cognitive ability  is influenced by it. 

Disruption of these rhythms has been linked to poor health outcomes. So, it makes sense that understanding and living in harmony with our body clock is important for health and wellbeing.

What drives our body clock?

Our body’s inner time-keeping system is made up of a central ‘pacemaker’ or ‘master clock’ located in the brain, called the suprachiasmatic nucleus (SCN). 

This distinct structure in the brain is comprised of about 20,000 nerve cells and is located in the hypothalamus. It sits just above our optic nerves, where it receives information about the amount of incoming light. 

A time-keeping powerhouse, the SCN coordinates the numerous biological clocks or specific molecules found in nearly every tissue and organ of the body. This in turn produces and regulates our circadian rhythms.

All up, it’s a complex and finely tuned inner architecture, designed to align our biological functions with environmental patterns (primarily, light and darkness), so we can function at our best.

How do you find your circadian rhythm?

We all experience a similar drive to wake when it’s morning, and increasing drowsiness as the evening wears on, but there are individual variations in our circadian rhythms, known as chronotypes. 

Early birds who have no trouble springing out of bed when the alarm goes off have an early chronotype. Night owls, who may be slow to start but perk up as the day goes on, have a late chronotype. 

While you can’t change your biological predilection to a certain chronotype, you can work with it. For instance, scheduling challenging work tasks for when you naturally tend to be most productive, and your workout for when you feel most energised. Read ‘How to get more energy’ for plenty of great energy boosting tips 

Tapping into better health

Given the far-reaching impact of our circadian rhythms on numerous physiological processes in the body, it follows that getting in step with these rhythms is supportive of good health. 

One of the simplest ways to do this? Prioritising sleep, and good sleeping patterns. Having a consistent sleep schedule, where you wake around the same time every morning and go to bed at the same time each night, even on weekends, helps keep your circadian rhythm in check. 

Aiming for between seven to nine hours shut-eye per night will also ensure you’re properly rested. 

Practising good ‘sleep hygiene’, for instance by having a soothing pre-bed routine and reserving your bedroom for sleep rather than work or entertainment, is also helpful.