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Sleep, Screens and Blue Light: Here’s What You Need to Know

“Blue-light emitting devices fool your brain into thinking that it’s still daytime, even though it’s night-time and you want to get to sleep.”

– Matthew Walker, Professor of Neuroscience and Psychology at the University of California, Berkeley, and author of Why We Sleep

Your screen time habits might be disrupting your sleep. Civil team members had lots of questions about this topic, like, “Is it ever okay to binge on British Bakeoff before bed?” and “Do night modes on devices work?” So we set out to find some science-based answers.

“Is it ever okay to binge on British Bakeoff before bed?”
The idea of not watching Netflix or playing video games after dark can be downright soul-crushing. Experts agree that TV and computer use before bed can make it harder to sleep because the blue light they emit interferes with melatonin production. But according to, blue light doesn’t just delay falling asleep. It deteriorates sleep quality, too. “Even if your eyelids start to droop while you watch TV, your sleep can still be affected. The blue light exposure can delay the onset of REM sleep and lead to morning drowsiness. In other words, even if you think that you’re sleeping fine, you might not be getting the quality sleep that you need.” So how early do you need to stop screen time? Harvard Medical School Sleep and Circadian Disorders researcher Dr. Shadab Rahman suggests powering down devices with screens a full two hours before bedtime.

“Do night modes on devices work?”
There is some evidence that suggests that light color can reduce or exacerbate the effects of evening screen time. A study in Chronobiology International found that looking at screens that gave off intense blue light cut someone’s sleep by about 16 minutes and woke up more often in the night, compared to displays with red light. People using screens that emitted a lot of blue light also made less melatonin than when they used screens with a higher proportion of red light. Another study suggests that color temperature is more critical than illumination level when it comes to light’s effect on your sleep. While it appears that warm or red light is better than cold or blue light before bed, the fact remains that all ocular light exposure disrupts melatonin, which throws off your circadian rhythm. There haven’t been any long term studies on apps and features like Night Shift, Night Mode, f.lux, and Twilight, so we don’t know their total impact on sleep quality. Based on the research, if you’re going to wind down with screen time before bed, using some kind of night mode setting may help with damage control.

Should I get blue-blocking glasses?
There are a variety of blue-blocking glasses on the market for every style and budget. For $10 you can get nerdy-looking UVEX specs. For $95 you can upgrade to stylish prescription eyeglasses from Felix Gray. But do blue-blocking glasses work? A study in the Journal of Adolescent Health reports that young boys who wore orange glasses while looking at their phones before bed felt “significantly more sleepy” than when they wore clear glasses. A similar study with adults found that by the end of the study, the subjects wearing blue-blocking lenses experienced significant improvement in sleep quality compared to a control group. The blue-blocking glasses are also marketed as a solution for eye strain, with a tester for Good Housekeeping reporting, “My eyes felt more rested at the end of the day (probably from the reduced screen time and glare) and looked visibly less red and tired.” So if you’re like everyone else and you spend a more-than-ideal amount of time looking at screens, or your device-of-choice for night viewing doesn’t filter out the blue light for you, then blue-blocking lenses are probably worth a try.

The Takeaway
We’re skeptics, but there is scientific support for the idea that reducing blue light can help you sleep better—even if you’re not decreasing screen time. Apps, device features, and blue-blocking glasses can help mitigate the harm of after-dark screen time, but the fact remains that light isn’t good for sleep onset or sleep quality. The ideal way to spend the last two hours before bed is offline, by candlelight.

We believe the amazing benefits of healthy, high-quality sleep should be accessible to everyone! Want to get a better night’s sleep starting tonight? Check out 5 Rules for Civilized Sleep* (that everyone can do). 

Author: Matthew Rader
Photography: Creative Commons

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