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In evolutionary terms, we have spent very little time living with and depending on artificial light. This dependency has been found to negatively affect our circadian clock, our connection to the light/dark, daily, and seasonal cycles. (1)
Every cell in the body is linked to a biological clock that turns certain functions on and off as day turns into night and summer transitions into winter. A new study has found that artificial light in our homes can cause our circadian clocks to be out of sync with nature’s clock.
Natural light changes dramatically throughout the day, but in an office, artificial light never changes—it is an unnatural, constant glow. In the winter, the days are shorter and nights are longer, suggesting we should sleep more in the winter… and now there is science to back that up! (1)
Long summer days trigger circadian changes inside of us that we are only beginning to understand, but it is safe to say that every cell cycles on and off based on these powerful seasonal changes.(1)
We are not the only species whose life depends on these light/dark cycles. Birds fly south, whales migrate and leaves change color. Life itself has evolved to depend on the circadian rhythms that are being challenged by an overdose of artificial light.
Being out of sync or disconnected from the circadian rhythms is called Chronodisruption (CD), and has been linked to a host of health concerns, such as:
- Poor cognitive function (1,3)
- Mood disorders (1)
- Sleep disorders (1)
- Diabetes (1,3)
- Obesity (1,3)
- Daytime sleepiness (1)
- Reduced school performance (1)
- Reduced driving reaction time (1)
- Substance abuse (1)
- Heart disease (3)
- Some cancers (3)
The Circadian Reset
In a new study, researcher Kenneth Wright at the University of Colorado evaluated the circadian clocks of a group of people by measuring melatonin levels–which should rise at night and fall during the day. Normally after the sun sets, melatonin levels start to rise and a feeling of sleepiness should naturally ensue. In the morning, right after sunrise and getting out of bed, melatonin levels should rapidly drop–allowing sleepiness to be quickly replaced with energy.
In this study, they found something shocking. About 2 hours after waking up, when the melatonin levels should have dropped, they started to rise again. This, of course, lead to mid-morning sleepiness and poor performance at work. This may explain the need for a coffee break about this time of day. Melatonin is considered the sleep hormone that is linked intimately to the light/dark cycles.
The researchers measured the effects of living without any artificial light for one week during a camping trip. During the camping trip, they went to bed and arose on their own, but there were no sources of artificial light except for a campfire. They measured the melatonin levels after a week of camping, and then compared them to their melatonin levels after a week of normal life using artificial light, televisions, computers, etc.
The results were amazing. After just one week of living in sync with the natural light/dark cycles, the group went to bed and woke up an average of 2 hours earlier. The mid-morning melatonin surge did not happen. Their clocks were reset!
The researchers then measured the effects of just a weekend camping trip to see if this would be enough to reset the clock. In this case, the campers went to bed and got up almost 1.5 hours earlier compared to their falling and rising time in artificial light-world.
In fact, in just one weekend camping trip, the researchers observed that the campers were able to achieve around 69 percent of the circadian shift-benefits that were achieved by an entire week-long camping experience. (1)
By naturally getting to bed earlier, the campers all naturally got up earlier and were able to enjoy the early morning natural light. The sun’s mornings rays are filled with blue light that suppresses melatonin and are, thus, capable of resetting the body’s circadian clocks.
In 1998, researchers discovered melanopsin retinal ganglion cells, which were a new type of photoreceptor in the eye. These cells provide signals to the suprachiasmatic nucleus (SCN), the brain’s master clock. The melanopsins project to numerous brain centers and have an impact on numerous brain and physiological functions. The melanopsins are particularly sensitive to blue light. (2)
Blue light, which is particularly beneficial during the daytime, seems to be more disruptive at night as it blocks melatonin production. Nocturnal blue light exposure is currently increasing, due to the proliferation of energy-efficient lighting (LEDs) and electronic device screens, which are 35% blue light compared to the sun, which has only 25% blue light. No wonder folks are having more trouble getting to sleep!
The study also confirmed what Ayurveda has been saying for thousands of years regarding seasonal circadian cycles. They found that melatonin levels will rise earlier in the evening and drop later after the sunset in the winter, when the days are shorter and the nights are longer. In the summer, the melatonin levels are delayed and rise much later in the evening, matching the longer days and the later sunset.
Reset your Internal Clocks this Weekend
Try some of these simple home strategies to help reset your circadian clock:
- Take a weekend and turn off the Wi-Fi, lock away your cell phone, turn off all the lights and use candles or/and a fireplace for evening light. Get outside for a hike or walk as much as possible. Go to bed in the early evening at the first sign of sleepiness and get up in the morning when your eyes first open. Get outside and take a morning walk as you watch the sunrise. Enjoy!
- During the week, turn off the house Wi-Fi after supper. Dim the house lights and avoid phones, televisions or computers. Go to bed reading a book by candlelight.
- On your next camping trip, don’t miss the great opportunity to reset your clock. Don’t turn on your phone and avoid flashlights. Make torches and a campfire. Enjoy!
- Consider getting outside and performing a yoga sequence, such as the Sun Salutation at sunrise and sunset.
Elfa Martinez says
Dear Dr. John,
All information you send is most helpful. I know that I can’t work on the computer, use the cell phone, or watch TV (which is rarely that I have time) after 7:30 or 8:00 PM because it disrupts my sleep. So the article on setting our circadian by using candlelight is most helpful. I will try it this 3 day holiday weekend. I don’t get out to exercise in the morning after getting up but I do Qui-Gong or other form of exercise inside for at least 20 min. that’s when I’ve had a good night’s sleep and I can get up at 5 to 5:30. Thanks, and I’m looking forward to using candlelight and observe what happens.
Rashmi says
Dear Dr. John,
I completely agree and understand the points you have made in the above article. Sometimes I do wonder if technology advancement has been the curse of our civilisation!
Like most other minions in today’s world, I too make a humble living with a modern day desk job that gets done at 6 every evening. I usually exercise after that ( since mornings are always in a rush no matter what) and as a consequence I have a late (but light) dinnerbetween 9-9:45pm. And then I just go to bed exhausted only to wake up at 7:30 and get some caffeine in me to get me going. I eat alright but I cant seem to break out of this vicious cycle because I really dont seem to be getting healthier or be able to have energy during the day. Is there any recommendation for people like us who have no choice but to sit at desks all day/ sleep when we should be awake and vice versa. I am tempted to quit but that isnt realistic. Any advice would be appreaciated!
Marsha says
Hello to Rashmi,
I am not Dr. John, but listen to as much of he’s offering to us. Rich in understanding, and application…
I don’t know what time you wake up before you leave for your job, and if there is a way to commit to adjusting an extra 15-20 minutes earlier, to do some exercises, or a stretch program, to get the circulation and lymph and heart and muscles moving…. Is it possible for you to walk outdoors for 20 minutes before leaving for your job to work, (I don’t know your environment or personal needs) but the natural light, even if it’s gray or raining, is still natural light. This daily commitment may help you shift somewhat to a better circadian rhythm, especially if it becomes a daily routine for you… Wishing you all the best, oh, and do you if exercising at night is stirring up your body, are you following a visual DVD for exercise at that time? If so, and if you are able to exercise in the morning, and in the evening, turn off computer and TV an hour before you sleep, you may find a re-set in your circadian rhythm… worth a good try as you are able. Be Well, Mar
Michaela says
Dear Dr. John,
I’ve enjoyed reading your articles for quite a while now, and have learned so much!
I’m very aware of the fact that shift work is unhealthy, and being an international flight attendant probably even more so. Still, do you have any advice? I’d be curious to hear your opinion on that!
? thanks ☀️
LifeSpa Staff says
Hi Michaela, you may enjoy this article from Dr. John https://lifespa.com/5-tips-to-survive-night-shift-long-hours-and-travel/
Perhaps the most powerful tool is lifestyle itself. Learn more about a healthy Ayurvedic lifestyle in sync with the circadian rhythms in this article: https://lifespa.com/live-with-the-cycles/