Students who text in the dark get less sleep and perform worse at school than those who put down their phones when they switch off their lights.

New research suggests that the sleep-delaying impact of ‘blue light’ emitted from phones is intensified in the dark, and results in students feeling sleepier during the day and performing worse in tests.

In contrast, texting before lights out was found to have no impact on academic performance.

The study adds to a small but growing body of evidence on the importance of sleep for teenage brains, suggesting it should be given the same weight as nutrition and exercise in promoting healthy bodies and minds.

The research, published in the Journal of Child Neurology, is the first of its kind to link the nighttime texting habits of American teenagers to school performance.

Author Xue Ming, professor of neuroscience and neurology at Rutgers New Jersey Medical School, says the study highlights the effects of smartphone use on teenage brains.

Children aged five to 16 spend more than six hours a day in front of a screen, well above the two hour recommendation of the American Academy of Pediatrics.
