The study, published in the Journal of Child Neurology, is the first of its kind to link nighttime instant messaging habits of American teenagers to sleep health and school performance.
“We need to be aware that teenagers are using electronic devices excessively and have a unique physiology,” says study author Xue Ming, professor of neuroscience and neurology at Rutgers New Jersey Medical School, in a release. “They tend to go to sleep late and get up late. When we go against that natural rhythm, students become less efficient.”
To conduct her study, Ming distributed surveys to three New Jersey high schools—a suburban and an urban public school and a private school—and evaluated the 1,537 responses contrasting grades, sexes, messaging duration, and whether the texting occurred before or after lights out.
She found that students who turned off their devices or who messaged for less than 30 minutes after lights out performed significantly better in school than those who messaged for more than 30 minutes after lights out.
Students who texted longer in the dark also slept fewer hours and were sleepier during the day than those who stopped messaging when they went to bed. Texting before lights out did not affect academic performance, the study found.
The effects of “blue light” emitted from smartphones and tablets are intensified when viewed in a dark room, Ming says. This short wavelength light can have a strong impact on daytime sleepiness symptoms since it can delay melatonin release, making it more difficult to fall asleep—even when seen through closed eyelids. –