Does using a device before bed make it harder to sleep?

Yes, it's true: The light from a phone, laptop, or other device confuses the brain into thinking it's time to wake up instead of fall asleep.

Light from electronic screens comes in all colors, but the blues are the worst. Blue light fools the brain into thinking it's daytime. When that happens, the body stops releasing a sleep hormone called melatonin. Melatonin is nature's way of helping us wind down and prepare for bed. The body starts releasing it a couple of hours before bedtime. Darkness helps trigger the release of melatonin; blue light delays it.

That's bad enough, but it gets worse: Teens are more sensitive to the effects of blue light than adults are. So you're more likely to be tossing and turning hours past your usual bedtime. Add that to the other things that make it harder to sleep — like body clocks that make us feel awake at night, more homework and distractions, and early school start times — and it's a recipe for feeling sleep deprived.

Some people try to get around the blue-light problem by dimming their screens or wearing special glasses. But there's no proof that these work.

To be sure your brain is at its best for tests, sports, and other things that require focus, don't use screens for an hour or two before bedtime. How do you fill that time? Call a friend instead of texting. Hang out with family. Play with a pet. Or try some breathing exercises.

Blue light is just one of the ways tech devices can interfere with sleep. It's best to shut off alerts when you go to sleep and keep devices that emit light out of your bedroom.