For years experts have advised parents to limit screen time, but if your child uses electronic devices you know how difficult it can be to get them to disconnect at the end of the day. TV’s, tablets and video games have an irresistible allure for even very young children, and today’s teenagers routinely do homework on laptops and use smartphones to socialize at night. It can be challenging to set limits and enforce them when electronics are such an integral part of our day to day lives.
Because the technology is relatively new, researchers are just beginning to understand the full impact of screen time on human health, but there’s one thing we already know for sure. The blue light from electronic screens can have a profoundly negative impact on sleep.
What is blue light?
Blue light is a color in the visible light spectrum with a very short wavelength, which means that it produces a high amount of energy. In the days before technology our only exposure to blue light was from the sun, but now we’re exposed constantly because fluorescent and LED lighting, televisions, tablets, computers and smartphones all emit high concentrations of artificial blue light. Studies show that blue light is more disruptive to sleep than any other color on the spectrum.
How does blue light affect sleep?
The absence of light signals the brain that it’s time for sleep and triggers melatonin release, the hormone that makes us drowsy. Any light can disturb that process, but high concentrations of blue light from digital devices are especially disruptive. Exposure before bedtime can suppress melatonin production for twice as long as any other color in the spectrum and can alter our internal clocks by twice as much as well. Studies have shown that blue light stimulates cognitive function and alertness, which is a plus during the daytime but a real problem at bedtime when it’s time to sleep. In short, exposure to blue light can make it harder to fall asleep, stay asleep, and get the amount of sleep we need.
How can I minimize exposure?
Unplug in the evening. I know it’s not easy to do, but setting limits around screen time in the last hour or two before bedtime is by far the best way to make sure that you and your children are set up for a good night’s sleep. Try for at least one hour of no screen time before lights out, and keep televisions, tablets, and smartphones out of the bedroom.
Use blue light filtering apps and software. Because of consumer awareness, many tech companies have already programmed blue light blocking settings into their products’ operating systems. For example, Apple products have a function called Night Shift that can be programmed to shift the display colors to the warmer, less stimulating end of the color spectrum during the evening hours. For devices that don’t have built-in programs, various apps can be downloaded to reduce exposure.
Try light filtering glasses. Several blue-blocking eyeglasses filter out the blue part of the light spectrum. A good pair will run about $80.
Use specialty light bulbs. Many companies make light bulbs that filter out blue light. The Lighting Science Good Night Light Bulb series (which was originally developed for NASA astronauts on the International Space Station) makes a series of bulbs, including and a baby nursery version to help parents reduce blue light exposure when changing diapers in the middle of the night. For families that are especially techno-savvy, Philips has a line of smart bulbs called Hue that connect with your home’s wireless network or smart-home systems like Amazon Alexa and Nest and allow you to program lighting in your home based on your family’s schedule (for example, you can program the system to dim the lights gradually in the evening and turn the lights up gradually in the morning to help you wake up.) Not surprisingly, these are pricey products compared to regular light bulbs, but they last a long time and can have a measurable impact on sleep if used strategically throughout the home.
Alison Bevan – Sleepytime Coach
Pediatric Sleep Consultant – The Center For Advanced Pediatrics