Preteens who look at a phone or television screen in the dark an hour before bed are at risk of not getting enough sleep compared to those who use these devices in a lighted room or do not use them at all before bedtime, according to a new study by U.K. and Swiss researchers.

The research is the first to investigate the pre-sleep use of screen-based media devices alongside the impact of room lighting conditions on sleep in preteens.

The findings show that night-time use of phones, tablets and laptops is consistently tied to poor sleep quality, insufficient sleep, and poor perceived quality of life. Insufficient sleep has previously been linked to poor immune responses, depression, anxiety and obesity in children and adolescents.

For the study, researchers from the University of Lincoln; Imperial College London; Birkbeck University of London and the Swiss Tropical and Public Health Institute in Basel (Switzerland) looked at the data of 6,616 adolescents, ages 11 and 12.

They found that more than 70 percent of participants reported using at least one screen-based device within one hour of their bedtime. The preteens were asked to self-report a range of factors including their device use in both lighted and darkened rooms, their weekday and weekend bedtimes, how difficult they found it to go to sleep and their wake up times.

The findings reveal that those who used a phone or watched television in a room with a light on were 31 percent more likely to get less sleep than those who didn’t look at a screen. The risk increased to 147 percent if the same activity took place in the dark.

“While previous research has shown a link between screen use and the quality and length of young people’s sleep, ours is the first study to show how room lighting can further influence this,” said lead author Dr. Michael Mireku from the University of Lincoln’s School of Psychology.

“Our findings are significant not only for parents but for teachers, health professionals and adolescents themselves. We would recommend that these groups are made aware of the potential issues surrounding screen use during bedtime including insufficient sleep and poor sleep quality.”

Research has shown that globally, 90 percent of adolescents are not sleeping the recommended nine to 11 hours per night, and this has coincided with an increase in the use of screen-based media devices.

Sufficient sleep duration and quality are vital during childhood to maintain physical and mental development. In addition, a lack of sufficient sleep has been directly related to poor academic performance.

Source: University of Lincoln