Light affects the hormone melatonin, which helps regulate sleep. In some it even does Blind people Without conscious awareness of light.
Researchers soon discovered why: Our retinas contain specialized cells that are uniquely sensitive to light at wavelengths of 460 nanometers, or blue light.
Blue light from the rising sun during the day That triggers retinal cells to signal to our brain Stop melatonin production. Then, as our environment darkens and the blue light is replaced by the warm hues of the setting sun, melatonin rises again, allowing us to sleep.
Scientists think that the cells in the retina that sense light are significant blue First evolved among the inhabitants of the seasWhere is the blue? Wavelengths penetrate the surface of water very easily.
Blue light and circadian rhythms
The human eye evolved to adapt to these natural light conditions, but electric lights—the incandescent bulbs patented by Thomas Edison in 1880—disrupted our circadian cycles. Modern societies then began to stay awake, work more hours indoors, and sleep in one continuous night instead of two shifts, known as biphasic sleep (That was once a thing)
We are now constantly exposed to blue light in the evening from the fluorescent lights, streetlights and headlights of our homes and offices.
It disturbed our sleep. A study Nearly 20,000 American adults People who live in areas with high levels of outdoor nighttime lighting, such as streetlights, have reported delayed bedtimes, less sleep, and increased daytime sleepiness.
Skyscrapers in cities have created “urban valleys”. Nature robs us of light – with a Great impact on our healthsaid Karolina Zielinska-TapkowskaA lighting designer and assistant professor of architecture at the Gdansk University of Technology in Poland.
In addition to disrupting sleep, artificial light exposure at night has been linked Breast And Colon cancer, Zielinska-Dabkowska said in an email interview. “It’s a risk factor heart disease, Type 2 diabetes, high blood pressure, obesity And Depression,” she said.
There are a few ways to regain control of our circadian rhythms.
“Exposure to daylight in the morning can have a positive effect on the quality of your sleep at night,” Zielinska-Tapkowska said.
Your circadian rhythm is more sensitive to light In the first hour of waking up. To get your biological clock working better, get blue-tinted sunlight early in your day without wearing sunglasses or contact lenses, she advises.
Afternoon lattes trade for walks outside
The body produces melatonin again lunch. Some cultures embrace melatonin-producing sleep and encourage siestas. Other cultures should descend on nearby Dunkin’s at 3pm for tea, coffee or Bostonian inspiration.
However, sunlight may stop Melatonin From telling you to hibernate. A Study among college students Early afternoon exposure to artificial blue light not only improves post-lunch sleep but also boosts memory.
Rethink your home lighting
Move your desk to a location that gets more natural light during the day.
Dim all lights at least three hours before bed.
The Lights should be subdued and blues should be minimized. On July 31, the United States will stop producing incandescent bulbs (known for their warm sunset-like spectrum), so until you can stash them away, switch your incandescent bulbs to amber LED bulbs, or better yet, smart bulbs. These are blue during the day and red in the evening (aim for 2,700 Kelvin or below).
“The placement of the light sources is also important,” Zielinska-Tapkowska said. Avoid overhead lighting and place lamps on the floor or on tables, with shades to avoid looking directly at the source, he suggested.
Change your phone’s settings
Avoid screen time before you go to sleep, but because it doesn’t always happen, turn on “Night Shift” setting on your iPhone or “Blue Light Filter” on Android phone Adjust your screen color in the evenings.
“These features do not completely reduce blue wavelengths,” cautioned Zielinska-Dupkowska, but they do “reduce some of the impacts of such devices.”
Experts recommend a room Not brighter than 1 lux During sleep – about three feet above the eye is equivalent to one candle. If your home has a lot of light pollution from outside, experiment with a sleep mask or curtains.
What my patients need to know
Taking small doses of melatonin is generally safe in the short term, but can be troublesome A high percentage Melatonin supplements do not contain what is on the label. Before trying the pill, if you have insomnia, talk to your doctor about cognitive behavioral therapy — our first-line recommendation because it addresses the underlying cause of your insomnia, as opposed to medications that target symptoms.
Visit Doctor: Trisha S. Basricha is a physician at Massachusetts General Hospital, a clinical instructor at Harvard Medical School, and a medical journalist.
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