Also known as your sleep/wake cycle or body clock, your circadian rhythm is your body’s 24-hour internal clock that regulates how sleepy or alert you feel at different times of the day.
It’s controlled by a region of the brain that’s sensitive to light, which explains why we are most wakeful during daylight hours and feel the need to sleep when it’s dark.
Our circadian rhythm works at its best when we keep regular wake times and bedtimes. Things like jet lag, shift work, staying up late and using electronic devices at night can throw it out of whack, making us feel groggy and out of sorts.
The good news is, it’s easy to keep your body clock ticking smoothly with these simple strategies.
1. Keep consistent bed/wake times
Our circadian rhythm likes routine and consistency. So, while it may be tempting to stay up late at night working, scrolling through social media or catching up on your favourite Netflix shows, and ‘catch up’ on sleep on the weekend, this disrupts the balance of your body clock.
Aim to go to bed around the same time, and wake at the same time every day, even on weekends.
2. Catch some bright light in the morning
Morning light signals to your body clock that it’s time to wake up, triggering a rise in body temperature and production of the hormone cortisol , which in turn switches on your appetite and energy.
Bright light also inhibits the release of the ‘sleepy hormone’ melatonin.
Getting bright light exposure in the AM by throwing open the blinds, having a morning power-walk or eating breakfast near a window, will support your body clock’s natural drive to alertness at this time, and help you shake off sleepiness.
3. Dim the lights in the evening
Just like bright light signals to your internal clock that it’s time to be awake, darkness plays a role in making you feel sleepy.
When daylight fades, the body’s pineal gland is ‘activated’ by the suprachiasmatic nucleus (the brain’s ‘master clock’ that controls the circadian clock) and begins to produce melatonin , in turn making you feel sleepy.
If you’re exposed to too much artificial light at night, it can hamper this process, interfering with your sleep drive. So, in the lead-up to bedtime, dim the lights.
4. Limit your screen time at night
Not only are smart phones, tablets and laptops mentally stimulating (which can make winding down harder), they emit blue wavelength light, which disrupts our body’s natural rhythms by delaying the circadian clock .
According to an evidence summary from the Royal Society Te Apārangi, New Zealand, this “makes it harder to fall asleep at night, to wake up in the morning, and impedes attention abilities the next morning.”
To mitigate the effects of blue light, the report suggests curbing your amount of screen time at night and reading a book or a non-light emitting eReader instead.
5. Move more to sleep better
Research shows that exercise is important for shut-eye, linking it to reduced daytime fatigue. Regular exercise also helps to reduce the time it takes to fall asleep and improves sleep quality.
When it comes to your circadian rhythm, the timing of your workout matters – and it seems daytime exercise is best.
Exercising at 7am or between 1pm to 4pm advances the body clock (which can help you start activities earlier in the day) whereas exercising between 7pm to 10pm delays the body clock, which means it may take longer to get into peak performance mode the next day, reports a 2019 study.
