Circadian Rhythms – Sync Your Sleep-Wake Cycles
A circadian rhythm is the cycle of biological activity that occurs approximately on a 24 hour cycle. Interestingly the cycle requires external cues such as light, timing of eating and activity to be set accurately.
It’s fascinating to think that every cell in the body is under the influence of a circadian clock. The master clock is located in the hypothalamus and is called the suprachiasmatic nucleus (SCN). One of the major signals to the SCN is the light and dark cycles of the day. Light exposure inhibits the release of melatonin and stimulates release of cortisol, feeding rhythms and body temperature. So basically synching our body to the day and telling it what needs to be done.
Once upon a time, we would spend much greater amounts of time outdoors and then at night sit by the fire or lamps that emitted very little blue light. Now in our modern world, we are spending most of our days inside and then exposing ourselves to light at night on a significant scale. In fact if you compare the light emitted on a full moon night, to that of an average living room, it is about 1000 times greater!
Then to further throw our circadian rhythms out, LED screens such as TVs, computers, tablets and phones emit blue light and what do most of us do at night? We watch screens!
So there is a lack of natural light during the day which is needed to signal the SCN to start the body’s daytime routine and then excessive light exposure at night, which reduces melatonin signalling, consequently disrupting sleep. Not only that, but disrupted circadian cycles have been shown to affect moods and increase anxiety and depression and also obesity.
Tips for a Good Nights Sleep
As more research highlights the benefits of getting 7- 9 hours sleep per night, we realise that our modern world is making this increasingly difficult to achieve. Let’s look at what can be done to support our natural circadian cycles:
- Avoid screens for at least 1 hour before bed- TVs, computers, tablets, phones or use a night filter if necessary.
- Aim for 30 minutes of sun exposure in the morning and ideally in the middle of the day and at twilight.
- Avoid caffeine after 12 pm – coffee, tea, energy drinks.
- Make sure the bedroom is dark or use eye masks if required.
- Turn off the phone or put it on airplane mode
- Have a nightly wind down ritual e.g. a warm bath, listening to relaxing music or a calming mindfulness App
- Write down any intrusive thoughts on a piece of paper or better still have a notebook ready at the bedside for any last minute concerns.
Our circadian rhythms are the rhythms of life and syncing our sleep-wake cycle is key to ensuring good health.