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Minimizing the Effects of Blue Light

As we spend more time at home during the coronavirus pandemic, we’re naturally exposing ourselves more to our screens. We keep staring at smart phones, laptops, and TVs. This, in turn, is increasing the amount of our exposure to the blue light that these devices emit.

Numerous studies as far back as 1958 demonstrated the disruption exposure to artificial light causes on the body’s circadian rhythm. Blue light—the kind emitted by computers, tablets, smartphones, and TV— inhibits sleep. And it is the most disruptive of the colors of the light spectrum.

In addition, our efforts to be more environmentally friendly are hurting our sleep patterns. Substituting LED and compact fluorescent bulbs (CFLs) for incandescent light bulbs means even more blue-light exposure. These newer bulbs produce more blue light, and our bodies feel the effects.

Therefore, our family practice doctors want to explain how the effects of excessive exposure to blue light can be bad for your health. Then we’ll show you steps you can take to minimize it.


Our 24-hour culture

Biologically, humans are wired to react to daylight and darkness (the circadian “clock”). Until relatively recently, we have spent millennia waking when the sun rises and becoming sleepy when it sets. The invention of electric lighting allowed us to throw off our biological imperatives and work whenever the demand requires it. We, in turn, have learned to think of night hours as just a continuance of the day’s activities. Now we work and play long past the time when our bodies are demanding rest.

This ‘round-the-clock culture has been costly from a health perspective. Not only for a good night’s sleep, but also with its possible connection to numerous other illnesses. Studies have shown that shift work and exposure to bright lights late at night are linked to increases in heart disease, diabetes, obesity, and both breast and prostate cancer.

One Harvard University study, for instance, put 10 volunteers on a schedule that interfered with their circadian rhythms. It found their blood sugar levels increased as a result, putting them into a pre-diabetic state. Harvard sleep researcher Stephen Lockley noted shortened sleep as a result of artificial light at night has been linked to increased risk for depression, diabetes, and cardiovascular problems.


Blue light’s effect on sleep

Blue light’s effect on sleep is possibly the most well known effect. It is the wavelength of light most associated with blocking the release of melatonin, the natural sleep hormone. And this is the light primarily emitted from electronic screens.

Blue light isn’t all bad, however. You need it during the day to keep you awake, and also to help regulate your circadian rhythm. Some studies have even found that daytime exposure to blue light showed improvements in subjects’ concentration, mood, and daytime alertness, as well as improved sleep. But excessive exposure at night is when it becomes a problem.

Although any kind of light at night can suppress the secretion of melatonin, blue light has a much stronger effect. For example, Harvard researchers compared the effects of blue light with an equal amount of green light exposure. They found the blue light suppressed melatonin for twice as long as the green light. It also shifted the subjects’ circadian rhythms by twice as much (three hours vs. 1 ½ hours).


Reducing blue-light exposure

So what can you do to minimize your exposure to blue light waves for improved health and more restful sleep? There are several ways to accomplish this.

If possible, turn off electronic devices, including television, at least two hours before bedtime. Even indirect exposure to blue light (out of your direct line of vision) can affect the receptors in the eyes that block melatonin production.

You can also try dimming the brightness of your electronics manually, or take advantage of the apps that will shift the light automatically from blue to more oranges and reds in accordance with sunrise and sunset times.

Studies have found, however, that one of the most effective approaches is the use of blue-light blocking glasses.

A National Institutes of Health (NIH) study ten years ago seemed to show that orange-lens glasses will block enough blue light to significantly reduce its effect on melatonin production. A more recent Consumer Reports study also found a type of orange-tinted glasses cut out almost all the blue light in the spectrum. Two other yellow-tinted lenses tested also cut blue light, but not nearly as significantly as the orange.

A more recent study, released last month from researchers at Indiana University and published in the Journal of Applied Psychology, produced similar results.

“Wearing blue-light filtering glasses creates a form of physiologic darkness, thus improving both sleep quantity and quality,” Christiano L. Guarana, assistant professor of management and entrepreneurship at the Indiana University Kelley School of business, said in a statement.

Look for glasses specifically designed to block blue light. Less-expensive orange-tinted glasses will not only block blue light, but other light, as well, making them impractical for use at night.


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