How Blue LEDs Affect Sleep
Research has found that exposure to blue light suppresses the production of the sleep hormone melatonin more than any other type of light.
Credit: Ng Wei Keong | Shutterstock.com

Fluorescent bulbs and light-emitting diodes (LEDs) have taken over lighting because they are more energy efficient and can provide better lighting than incandescent bulbs. They are found in everything from task lighting to televisions to smartphones. But while these bulbs are helpful in many ways, they can also have a negative effect on sleep.

All artificial light, including LEDs, fluorescent bulbs and incandescent bulbs, can interrupt normal sleep patterns. The body's biological clock works in rhythms that are set by the amount of light and dark the body is exposed to. This is called the circadian rhythm. Circadian rhythms control the timing of many physiological processes. They determine sleeping and feeding patterns, as well as brain activity, hormone production and cell regeneration. 

When the body is exposed to only to the natural light of the sun, the hypothalamus area of the brain sets its sleep patterns according to when it is light outside and to when it is dark. Light is detected by the retina, which sends signals to the hypothalamus. When it starts getting dark outside, the hypothalamus signals to the body to start creating sleep hormones, like melatonin, and to drop the human's body temperature to prepare for sleep, according to the National Sleep Foundation. In the morning, when light is sensed, the body is told to warm up and to produce hormones, like cortisol, that wake the body up.

When artificial light is added to a human's day, the body's natural rhythms become confused. The retina can now receive light no matter what time of day it is, so the body doesn't know when to get ready for sleep. A study published in the Endocrine Society's Journal of Clinical Endocrinology & Metabolism found that, when compared with dim light, exposure to room light during the night suppressed melatonin by around 85 percent in trials.

Fluorescent and LEDs bulbs create a two-fold problem when it comes to sleep. First, they produce artificial light. Second, they produce blue light. 

Blue light wavelengths produced by electronics and overhead lights boost attention, reaction times and mood, according to Harvard Medical School. This can be great for the daytime when the body needs to be alert, but at night it can become a problem.

Research has found that exposure to blue light suppresses the production of melatonin more than any other type of light. It is believed that the shorter wavelengths in blue light is what causes the body to produce less melatonin because the body is more sensitive to this type of light. 

"In terms of light and our brains, there is a spectrum of wavelengths that impacts the human circadian system," said David Earnest, a professor and circadian rhythms expert at the Texas A&M Health Science Center College of Medicine. "Blue light is the most sensitive side of the spectrum."

A study by the University of Toronto found that those who wore glasses that blocked blue light wavelengths produced more melatonin than those who didn't during night shifts. Other studies have found that blue wavelengths suppress delta brainwaves, which induce sleep, and boost alpha wavelengths, which create alertness.

To get better sleep, it would be best to stop using artificial light altogether, but that isn't possible in modern times. There are some more reasonable solutions, though.

"To prevent sleeping problems, avoid any exposure to blue light 30 to 60 minutes prior to bed. That means, no TV, tablets, computers or smart phones," said Dr. Robert Oexman, director of the Sleep to Live Institute. "Ideally, you want your environment to be dimly lit so your body can start naturally producing melatonin."

Andrew Simon, a naturopathic physician at the Bastyr Center for Natural Health, also suggested changing all overhead lights to full spectrum if possible, and to use some of the new smart home tech solutions to have lights turn off gradually or at a certain time, to help encourage the body's natural sleep/wake cycle. 

If these steps aren't possible, dimming devices and wearing blue light filtering glasses can help.

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