Blue Light and Sleep

Courtesy of Wikimedia commons

Courtesy of Wikimedia commons

Have you ever been really tired and pushed through an internet homework assignment, but then couldn’t fall asleep, no matter how hard you tried? It’s probably because your screen, though turned off, is keeping you up.

According to the CDC, “Exposing the eyes to blue light (or white light, which includes blue light) during the sensitive periods triggers photoreceptors in the retina to send a signal to suppress melatonin and shift circadian rhythms. These photoreceptors do not respond to red light and minimally respond to yellow and orange light.”

As day turns to night and your immediate environment becomes dark, your body produces a chemical called melatonin, which controls when you sleep. The best way to obtain a good night’s sleep is to habitually go to bed at the same time every night, then wake up the following morning at the same time every day, even on weekends. This helps your body know when to produce more melatonin to help you get to sleep faster and wake up feeling more refreshed. However, life often causes difficulty forming such habits.

Every time you look at a screen, whether it’s a computer, phone or tablet, you get extra amounts of what’s called “blue light”. This light is brighter than what is considered “natural light”, and causes a disruption in your body’s natural clock—or circadian rhythm.

By interfering with the circadian rhythm, the blue light confuses your brain and causes it to believe it’s daytime, when you should be up and going about your life. As a result, it doesn’t produce the melatonin that would ordinarily put you to sleep, causing you to stay up later.

Needless to say, putting away technology is the simplest solution to this problem. However, modern technology is hard to say no to; many people use it as their primary source for communication, timekeeping and entertainment.

To combat this, there are apps that cast a colored glow across your device that attempts to cancel out the disruptive blue light. Color variations are available depending on the app and the user’s preferences.  

Amazon has added a Blue Shade feature to their Kindle Fire devices that, when enabled, alters the colors on the screen toward the warmer end of the spectrum, thus dramatically reducing the amount of blue light you see.

According to Apple, Inc., they’ve also added a blue-light-reducing feature: “Night Shift uses your iOS device’s clock and geolocation to determine when it’s sunset in your location. Then it automatically shifts the colors in your display to the warmer end of the spectrum, making it easier on your eyes. In the morning, it returns the display to its regular settings,” Apple said.

Other companies have put out a “night mode”, in which the background turns black and the text turns white. This doesn’t truly block blue light, but it can help some readers under low light conditions. Many third-party apps are

These color shifts aren’t perfect solutions to the problem, but they’re a good starting point. Prolonged exposure to blue light late at night can cause long-term damage to not only your memory, but also your immune system, which, according to


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