Teens who use screens more sleep less

Teenagers who use smartphones, laptops, and tablets more often than their peers take longer to fall asleep and sleep for less time overall.

Researchers surveyed more than 10,000 16-to-19-year-olds from Norway, questioning them about their use of electronics and sleeping habits. Those who used gadgets including MP3 players, video game consoles, tablets, smartphones, and computers for more than five hours a day were three and a half times more likely to sleep for fewer than five hours at night and 49 percent likelier to need more than an hour to get to sleep. "There was a gradual increase up to this point," lead author Dr. Mari Hysing said. "The more you spent on devices during the daytime, the less you slept, and the longer it took to fall asleep." The research confirms long-standing assumptions about the effects of electronic devices on sleep, but scientists say the exact mechanisms at work still aren’t clear. Light from electronic devices could be affecting teenagers’ body clocks, for example, or there could be less obvious effects, such as the emotional stimulation from chatting with friends.