A circadian rhythm is a natural 24-hour timing system that is present across all kingdoms of life. In humans, it is the internal clock that regulates the body’s essential functions and processes, optimising behavior and physiology. One of the most well-known and well-cited circadian rhythms is the sleep-wake cycle. This blog takes a look at how exactly you can improve and maintain your circadian rhythm.
- Timing is key to managing your circadian rhythm
- Lack of exposure to the right kind of light can disrupt sleep in more than one way
- Poor sleep can have consequences outside of the next day
When properly aligned, a circadian rhythm can be a powerful tool for our wellbeing. It can promote a restorative, reliable, and healthy sleep pattern. Research is beginning to reveal the vital role it plays in your overall physical and mental health. A poorly managed circadian rhythm has been linked to significant sleeping problems and has even been attributed to the cause of insomnia in some cases. Going to bed later on just one day of the week can affect your circadian rhythm. Experts think that differences by just two hours could impact sleep, potentially jeopardising your weekday routine.
With that in mind, how can a poor circadian rhythm be detrimental to health?
The Consequences of Sleep Disruption
In modern societies, sleep disruption is perhaps more widespread than ever before. A large proportion of the world’s population is at risk of environmentally driven sleep disruption. The majority of us are exposed to less natural light throughout the day and more artificial light at night. Clinical research has found that this may impair our circadian system’s organisation and disrupt sleep. Intensive, careful studies have shown that lack of natural light may have an array of metabolic health consequences.
Research has also found that sleep deprivation can lead to degrading:
- Cognitive ability;
- Your ability to pay attention;
- Feeling alert and ready;
- And, importantly, your memory.
These issues may be further compounded by people being more susceptible to poor dietary choices when they are not in tune with their circadian rhythm.
So how can you avoid this and keep your circadian rhythm in sync?
Adapt your Lighting
Before the creation of artificial light, people spent their evenings in relative darkness. Nowadays, the majority of the world is illuminated, a detail that we take for granted. There may, however, be a price to pay for basking in all that light. Blue-light in particular can cause our circadian rhythm to become out of tune due to the increased exposure to light at night. Any form of light can quell the secretion of melatonin, (a hormone that is responsible for influencing circadian rhythms), and blue-light does so more forcefully. Research from Harvard and colleagues compared blue and green light exposure with similar brightness. They found that the blue-light suppressed the melatonin for around twice the length of the green-light. It even shifted circadian rhythms by twofold (3 hours vs. 1.5 hours).
But, don’t worry this does not mean you need to spend your evenings in complete darkness! To protect yourself from the effects of artificial light, try following advice from Harvard:
- Replace night lights with dim red lights (red is far less likely to cause a shift in circadian rhythm and suppress melatonin).
- Limit screen time 3 hours before you go to bed
- If you use a phone at night, consider buying a pair of blue light glasses, or if not possible use Windows Night Light / Apple Night Shift features.
And importantly, make sure to get as much exposure to bright light throughout the day.
So why is natural light so important?
Soak in the sunlight
As mentioned before, one of the main contributing factors to sleep deprivation is the lack of natural sunlight. According to DR Charles Czeisler of Harvard Medical School, “Daylight keeps a person’s internal clock aligned with the environment.” The best remedy for this is to get outside at least once a day and soak up as much natural light as possible. The modern lifestyle often does not co-operate with the way our circadian clocks would want us to. By staying in for too long, our body rarely knows when it’s daytime and when it’s nighttime (the blue-light from all our screens doesn’t help as well). Research has found that this can cause delays in melatonin production which can have a consequence of keeping us up at night. Exercising can be a great tool to get you out of the house and boost your mood. Try to stick to a morning routine as research has found that exercising too late may cause a rise in your cortisol levels, potentially disrupting your sleep so late-night runs or gym sessions may not be the answer. Exercise won’t necessarily regulate your circadian rhythm, however, it helps to keep a consistent routine.
Routines in general are fantastic for maintaining your circadian rhythm. Eating patterns and meal timings fall under the circadian rhythm diet umbrella (i.e. the body clock diet) and help to keep you in sync with your internal clock. In other words, this means that you should be eating your full diet in the 12 daylight hours of the day and then fast for the remaining 12 at night. Jessica Tong, as a registered dietitian, recommends aiming “to make breakfast and lunch your larger meals and dinner your small meal of the day.” She also mentions that cutting down on midnight snacks could be a good place to start. Further research suggests that the human molecular clock, “may be regulated by feeding time and could underpin plasma glucose changes.” Whilst anyone can benefit from this dietary routine, it may be more effective for those with metabolic diseases, for example, type 2 diabetes or obesity. With that said, before you kickstart a new diet, consult a health professional to make sure it is right for you.
Check out our recipe ideas and keep track of all your meal plans inside the sydTM app.
Foley, Logan. “Circadian Rhythm: What it is, what shapes it, and why it’s fundamental to getting quality sleep.” Sleep Foundation. (2020). https://www.sleepfoundation.org/circadian-rhythm.
Goel, N., Basner, M., Rao, H., Dinges David F. “Circadian Rhythms, Sleep Deprivation, and Human Performance.” Progress in molecular biology and translational science. 199 (2013): 155-190. doi: 10.1016/B978-0-12-396971-2.00007-5.
Harvard Health Publishing ¦ Harvard Medical School. “Blue light has a dark side: What is blue light? The effect blue light has on your sleep and more.” Harvard Health Letter. (2020). https://www.health.harvard.edu/staying-healthy/blue-light-has-a-dark-side.
Nazish, Noma. “Everything You Need To Know About The Circadian Rhythm Diet.” ForbesLife. (2020). https://www.forbes.com/sites/nomanazish/2020/02/29/everything-you-need-to-know-about-the-circadian-rhythm-diet/?sh=214ccbe873f0.
Potter, Gregory D. D., Skene, Debra J., Ardent J., Janet E. C., Grant Peter J., Hardie Laura. “Circadian Rhythm and Sleep Disruption: Causes, Metabolic Consequences, and Countermeasures.” Endocr Rev. 37.6 (2016): 584-608. doi: 10.1210/er.2016-1083.
Tong, Jessica. “What Does Nutrition Mean to You?” https://www.jessicachanrd.com/.
Wehrens, S., Christou, S., Isherwood, C., Middleton, B., Gibbs, M. A., Archer, S. N., Skene, D. J., & Johnston, J. D. “Meal Timing Regulates the Human Circadian System. Current Biology, CB. 27.12 (2017): 1768–1775.e3. doi:10.1016/j.cub.2017.04.059.