It’s almost impossible to keep teens off their phones in bed - but new research shows it really does affect their sleep

New research challenges screen time guidelines for adolescents, showing screens in bed harm sleep quality more than pre-bed use.

Parents of children and teenagers have long been warned about the dangers of screen time and digital devices before bed – the worry being that screens could harm the sleep patterns of young people.

But do screens really hurt the length and quality of sleep? Our new research found that using screens in bed was worse for sleep than using screens for hours before going to bed.

Sleep guidelines recommend no screen use in the hour or two before bed. But we found screen time in the two hours before bed had little impact on young people’s sleep. Instead, it was screen time once in bed that caused problems.

Using cameras to track device usage and sleep, we found using a device in bed could cause more harm than screen time right up to bedtime. These findings challenge long-held assumptions about screen time at night and could help parents improve the quality of their children’s sleep.

A number of global organisations recommend adolescents stop using devices in the hour or two before bed, and instead undertake activities like reading a book or quiet time with the family.

But these recommendations are based on research with a number of limitations. The studies were designed in such a way that researchers could link sleep and screens. But they don’t tell us if changes in how young people used screens had an affect on the length or quality of sleep.

Most of the existing research also used questionnaires to assess both screen time and sleep. Questionnaires are unlikely to capture true screen time accurately, particularly if you are interested in knowing more than just how long an adolescent has spent on their device.