The evidence is piling up: Blue light from phone and computer screens could make it harder for you to fall asleep. 

Apple and Microsoft have tackled this issue by baking new features into their operating systems. You can now turn on nighttime settings to filter out the blue tones that trigger the nervous system to become more wakeful, interfering with sleep for people who use the devices before going to bed.

The science behind these features is convincing, according  to James Stringham, a psychology researcher at the University of Georgia. “There’s a plausible rationale for blue light filters to work," he says. "Fundamentally, if you reduce blue light with a yellowish filter, that certainly would help.”

Insomnia is a problem in need of solutions. In a Consumer Reports survey, 27 percent of U.S. adults said they had trouble falling asleep or staying asleep most nights, and 68 percent—or an estimated 164 million Americans—struggled with sleep at least once a week. 

Good Night's Sleep

Directions on how to adjust screen settings for iPhones, Macs, and Windows computers are outlined below. Google's laptop and phone operating systems are lagging behind.

Only a few Android phones, including the Google Pixel and Samsung Galaxy S8, have an official blue light filter. Google is "working on bringing blue light filters to Chrome OS but we don't have a timeline to share at this time," a company spokesperson says.

Stringham says he's heard of Chromebook or Android phone users who have found it helpful to wear blue blocker glasses in the evening. Additionally, a number of popular apps available in the Google Play Store and Chrome Web Store can add blue light filtering. Consumer Reports hasn't evaluated these apps either for how well they work or for how well they respect user privacy, so downloader beware. 

Using 'Night Shift' on Your iPhone or iPad

Settings > Display & Brightness > Night Shift
Apple introduced Night Shift last year, a feature that allows you to adjust the color of your screen based on the time of day. Any iPhone or iPad running iOS 9.3 or later automatically enables this feature. 

In the Display & Brightness section of the Settings menu, you can set Night Shift to start and end automatically, either by specifying hours or by clicking on Sunset to Sunrise. You can also adjust the intensity of the "color temperature" in this menu, sliding a control toward "more warm" for less blue light to "less warm" for more blue light.

To turn Night Shift on or off manually, go to the Control Center, which you access by swiping up from the bottom of the screen. 

Using 'Night Light' on Your PC

Start Menu > Settings (or Gear Icon) > System > Display > Night Light
Microsoft included its blue light filter, Night Light, in the Windows 10 Creators Update released a few weeks ago.

As with Apple’s Night Shift, you can schedule this function to automatically turn on and off at sunset and sunrise. If you're an early riser, you can set your own schedules here, too. Or you can toggle the feature on and off manually.

You can customize the intensity of the color shift by moving a slider. Move it to the left to make the display appear more red (with less blue light); move to the right to reduce the effect.

Note: If the slider is grayed out, you might have to update your display's driver.

Using 'Night Shift' on Your Mac

Apple Menu > System Preferences > Displays > Night Shift
Apple added Night Shift to computers with the macOS Sierra 10.12.4 update earlier this year. It works the same way as the iPhone version. You can schedule when you want the function to start and adjust the intensity of the color temperature change.

You can also turn Night Shift on or off manually by using the Notification Center on your desktop, either by clicking the icon on the top right corner of the screen or by doing a two-finger swipe on your trackpad or Magic Mouse. 

Other Steps to Take

"It's more than just the blue light that's keeping you awake" when you're using a phone or laptop at bedtime, Stringham says. "If you're working, obviously you're engaged in something."

Social media feeds and videos of kittens doing cute stuff are stimuli that tend to keep people awake and clicking. 

Standard bedtime advice applies whether you have a blue light filter or not: Set a schedule, avoid caffeine at night, create a comfortable sleeping arrangement, and, of course, avoid any electronics before bed (that includes TV). All of these steps will be conducive to a good night's rest.