How To Optimize Your Circadian Rhythm
Circadian rhythm comprises the physical, mental, and behavioral changes that occur over a 24-hour cycle in humans, plants, animals and microbes. 2
In the modern age, artificial lighting is the most significant disruptor to our circadian rhythm - it confuses our body as to what time of day it is. Artificial lighting impacts us by suppressing melatonin - a hormone secreted from the pineal gland which tells your body that it is nighttime. As a result, the physiological events regulated by melatonin are altered.
When our circadian rhythm is out of sync, it can have disastrous consequences. Disruption of the circadian rhythm is associated with numerous health consequences, such as:
Increased risk of premature death
Cancer
Metabolic Syndrome
Cardiovascular dysfunction,
Immune dysregulation,
Reproductive problems,
Mood disorders, and
Learning deficits 3
Having a well-tuned circadian rhythm is vital to overall health. We will thrive the most when our circadian rhythm functions in line with our natural environment. Here are some ways that you can best optimize your circadian rhythm:
Start your day with morning sunlight
As soon as possible after you wake up, expose yourself to morning sunlight. The sunlight will tell your body that it is time to start the day, and it will tell your light-sensitive suprachiasmatic nucleus (SCN) to trigger a shot of hormones and cortisol to help your body wake up. 1 You may pair your sun exposure with a walk to get your energy flowing or some yoga or stretching.
Where I live in Canada, there are certain times of the year when the days are very short. Around the winter solstice, we get less than 8 hours of total daylight. Shorter days present a challenge for those aiming to match their daily routines with the sun. While on longer days, I love to start my morning with a walk, by the time I have to come back inside to start work on shorter winter days, the sun is just barely rising - not to mention that walking alone on the dark empty streets of the city is not as safe.
Taking the shorter days into account, I have modified my winter schedule so that I can still anchor my circadian rhythm. I wake up consistently at 6:30 and go to the living room for some morning stretches in front of my bright red light panel, mimicking the sun's rise through colour and brightness.
After stretching in front of the red light for a few minutes, I feel quite alert, and I get dressed for either a workout in the condo gym or a session of hot yoga a short walk from my apartment. By the time I begin exercising, any grogginess from waking is completely gone.
My morning exercise routine helps me thrive by keeping me consistent. When I used to exercise after work, whether or not I actually went depended on what I had to cook for supper, what other plans there were that night or my energy levels at the end of the day. Having consistency in my routine helps me to regulate my circadian rhythm.
After I’ve finished my morning routine and am ready to start work, I try to take the time to step outside for a minute and bask in the morning light from the sun to help my body anchor itself in the time of day.
Take breaks outdoors
Humans are not designed to spend all day in a dark house, never being exposed to the sun. Even though the lights in your home may seem bright, comparatively, they are no match for sunlight, even on a cloudy day. Unfortunately, it does not work this way in the evening - artificial lighting at night will suppress your melatonin, affecting your sleep. The sunlight helps us regulate our body clocks, and when we don't get sun exposure, our bodies can get a little lost.
I try to take multiple breaks a day to step outside. I often spend my lunch break on a walk, whether it is to run a specific errand or just take a quick trip around the block. In addition to this, I will poke my head outside or step out on my patio for about a minute once and a while throughout the day to remind my body what time it is.
On long summer days, I will get to enjoy more sunlight after work and often will witness the transition from day to dusk. When I get to spend a large portion of the day outside and watch the sunset, I feel great and ready to sleep at the end of the day.
Maintain a consistent eating schedule
Satchin Panda, Ph.D.’s “The Circadian Code,” outlines numerous benefits to practicing Time Restricted Eating. Practicing Time Restricted Eating means keeping a consistent eating window - for example, eating your first meal at 9 am and your last meal at 5 pm. Keeping an eating window of 12 hours or less has been associated with weight loss in overweight individuals, as well as improved sleep and energy during the day. (Panda, 2018, p. 98)
When the eating window is reduced even more, down to 8 hours a day, benefits can increase even further. This eating pattern would be typically described as intermittent fasting. Benefits include increased fat-burning, and improved working memory, blood pressure and resting heart rate. 4
Making sure that your eating window is earlier rather than later in the day is important for a couple of reasons. One, your insulin response is better during the first half of the day. Two, melatonin should begin to rise 2 to 4 hours before bedtime, and melatonin affects blood sugar. (Panda, 2008, p. 99) This is one reason why you should make sure to stop eating a minimum of 3 hours before going to sleep, in addition to optimizing digestion and sleep.
Limit light exposure after sunset
After the sun goes down, I try to adjust the lighting inside of my apartment to mimic the light outside. I eventually grew frustrated with the bright overhead lighting in the kitchen and bathroom and tried to use some electronic candles instead. Finally, I came up with the more convenient idea of installing red lights in my home.
Red lighting is a more circadian rhythm-friendly option at night, mimicking the colour of the setting sun, campfire or candle that our ancestors would have been accustomed to before the recent introduction of electricity.
It is important to make sure that red lighting is not too bright, as the degree of brightness can also impact whether or not your circadian rhythm is disrupted. I took care to install the lighting so that it was below eye level and directed toward the floor to limit the amount of light shining into my eyes.
Conclusion
Optimizing your circadian rhythm is a lesser-known strategy that you can use to boost your health. It can really pack a punch because it impacts so many of your body’s processes - including sleep, digestion and hormones. Ensuring that you have a healthy circadian rhythm will help you to boost your health now and in the future by helping to prevent chronic disease.
Disclaimer:
The information on Better Health Project is intended for educative and informational purposes only and is not intended to serve as professional or medical advice. The content of this site is not written by a medical professional. Always seek the advice of a trusted and qualified healthcare professional before making health changes.
Further Reading
The Circadian Code, by Satchin Panda, PhD
Sources
Sleep/Wake Cycles. (2019, November 19). Johns Hopkins Medicine. https://www.hopkinsmedicine.org/health/conditions-and-diseases/sleepwake-cycles
National Institute of General Medical Sciences. (n.d.). National Institute of General Medical Sciences (NIGMS). https://nigms.nih.gov/education/fact-sheets/Pages/circadian-rhythms.aspx
Evans JA, Davidson AJ. Health consequences of circadian disruption in humans and animal models. Prog Mol Biol Transl Sci. 2013;119:283-323. doi: 10.1016/B978-0-12-396971-2.00010-5. PMID: 23899601.
Intermittent Fasting: What is it, and how does it work? (2022, October 20). Johns Hopkins Medicine. https://www.hopkinsmedicine.org/health/wellness-and-prevention/intermittent-fasting-what-is-it-and-how-does-it-work
