My mom says I need to stop using my phone and laptop before bed because the light makes it harder to sleep. Is that really true? – Ash* Yes, it's true: The light from a phone or laptop 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. The best way to be sure your brain is at its best for tests, sports, and other things that require focus is to follow your mom's advice: Don't use computers and other 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. *Names have been changed to protect user privacy. Back to Articles Related Articles Common Sleep Problems Sleep problems can keep some teens awake at night even when they want to sleep. If that sounds like you, find out what you can do. Read More 5 Ideas for Better Sleep Insomnia can be a big problem for teens. Read our tips on getting a good night's sleep. Read More What Should I Do If I Can't Sleep? Find out what the experts have to say. Read More Technology: 5 Ways To Reboot Yourself Sending and receiving messages late at night can disrupt your sleep and leave you tired and unfocused when it's time for school. Read More How Much Sleep Do I Need? Teens need about 8 to 10 hours of sleep each night. But you might not be getting it. Here's why - and tips for getting more shut-eye. Read More Note: All information is for educational purposes only. For specific medical advice, diagnoses, and treatment, consult your doctor. © 1995-2021 KidsHealth®. All rights reserved. Images provided by The Nemours Foundation, iStock, Getty Images, Veer, Shutterstock, and Clipart.com.