Light affects melatonin, a hormone that helps regulate sleep.partly so blind people There is no conscious perception of light.
Researchers soon discovered why. Our retina contains specialized cells that are uniquely sensitive to light with a wavelength of about 460 nanometers, or blue light.
At dawn, the blue light from the morning sun Triggers retinal cells to send signals to the brain To stop the production of melatonin. Then, when the environment darkens and the blue light is replaced by the warmer shades of the setting sun, melatonin increases again, allowing us to sleep.
Scientists hypothesize that it is important that the cells in the retina that perceive light are blue. first evolved among sea dwellersblue Wavelengths penetrate water more easily.
Blue light and circadian rhythm
The human eye has evolved according to these natural light conditions, but electric lighting (the incandescent light bulb was patented by Thomas Edison in 1880) disrupted the human circadian cycle. Modern society has led us to stay up late, work long hours indoors, and sleep one night in a row instead of two shifts known as biphasic sleep.it was once).
We are now constantly exposed to blue light in the evening, from fluorescent lights in our homes and offices, street lights and headlights during rush hour, and screens and smartphones we stare at while lying in bed.
It had a huge impact on our sleep.Research about 20,000 American adults People living in areas with more outdoor night lighting, such as street lights, were found to go to bed later, sleep less, and feel more sleepy during the day.
The construction of skyscrapers in cities has created “urban canyons”. rob us of natural light – with have a huge impact on our healthSaid Karolina Zielinska-Dubkowskalighting designer and assistant professor of architecture at Gdansk University of Technology, Poland.
In addition to disturbing sleep, exposure to artificial light at night can chest and colorectal cancerZielinska-Dabkowska said in an email interview. “It’s also a risk factor cardiovascular disease, type 2 diabetes, hypertension, obesity and depression,” she said.
There are several ways to regain control of your circadian rhythm.
“Getting sunlight in the morning can have a positive impact on your nighttime sleep quality,” says Zielinska-Dabkowska.
Your circadian rhythm is very sensitive to light within the first hour after waking. To maximize her body clock, she advised exposure to blue-rich sunlight early in the day, ideally without sunglasses or contact lenses. .
Take a walk outdoors in exchange for an afternoon latte
the body then produces melatonin again lunch. Some cultures accept the drowsiness caused by melatonin and recommend napping. Other cultures face this situation with tea, coffee, or the Boston urge to go to the nearest Dunkin’ at 3pm.
However, sunlight may stop melatonin From telling you to doze off.a study with college students showed that exposure to even artificial blue light in the early afternoon not only improved post-lunch sleepiness, but also improved memory.
Review your home lighting
Move your desk to an area that receives the most natural light during the day.
Dim all lights at least three hours before bedtime.
of Lighting should be subdued and blue should be eliminated. On July 31st, the United States will stop producing incandescent light bulbs (known for their warm, sunset-like spectrum), so unless you stock up on incandescent bulbs, replace fluorescent bulbs with amber LED bulbs, or preferably smart bulbs. is needed. These can be programmed to be bluer during the day and redder in the evening (aim for 2,700 Kelvin or less).
“The placement of the light source is also important,” says Zielinska-Dabkowska. She recommended avoiding overhead lighting, placing lamps low on the ground or table, and shaded to avoid looking directly into the light source.
Change your phone settings
Avoid screen time before bed. However, since this is not always possible, “Night Shift” settings on iPhone or “Blue Light Filter” on Android phones Adjust the color of the evening screen.
“These features don’t completely reduce blue wavelengths,” warned Zielinska Dabkowska, but “the impact of such devices is mitigated to some extent.”
The rooms recommended by experts are: Brightness less than 1 lux During sleep, it’s the equivalent of a candle a little over three feet away from your eyes. If you get a lot of light pollution from outside your home, try a sleep mask or blackout curtains.
What we want our patients to know
Low doses of melatonin are usually safe in the short term, but alarmingly high percentage of melatonin supplements do not contain what is listed on the label. If you have insomnia, talk to your doctor about cognitive-behavioral therapy before trying pills. We recommend cognitive-behavioral therapy as the first choice because it can address the underlying causes of insomnia, as opposed to medications that target symptoms.
Physician Profile: Trisha S. Pasricha is a physician at Massachusetts General Hospital, a medical lecturer at Harvard Medical School, and a medical journalist.
