The longer a teenager spends on screen time before going to bed, the worse the quality sleep they are likely to have, says a large study from Norway reported in the British journal BMJ Open.
The researchers say it’s time to update the recommendations on the healthy use of electronic devices, and extend them to tablets and smartphones.
The study of almost 10,000 16 to 19 year olds asked how much screen time they spent outside of school hours and on what activities, for any of the following electronic devices: computer; smartphone; Mp3 player; tablet; games console; and TV.
Some gender differences emerged in activities and preferred devices. Games console use was more popular among the boys and girls were more likely to use smartphones and Mp3 players.
Girls spent significantly longer on their computers chatting online while boys spent longer playing games on consoles and computers.
Almost all of the teens said they used one or more electronic devices shortly (an hour) before going to bed.
Although frequency of use differed among the various devices, use of any device during the day and in the hour before bedtime was linked to a heightened risk of taking longer than 60 minutes to get to sleep.
Total daytime screen use of more than four hours was linked to a 49% greater risk of taking longer than 60 minutes to fall asleep.
On average, the teens said they needed eight to nine hours of sleep to feel rested.
But those who spent more than two hours emailing or chatting online were more than three times as likely to sleep for less than five hours.
While those who spent more than four hours in front of any screen were more than 3.5 times as likely to sleep for less than five hours.
Multi-taskers, or those using more than one device, were also more likely to take longer to get to sleep and to sleep for less than those who used only one device.
“The recommendations for healthy media use given to parents and adolescents need updating, and age specific guidelines regarding the quantity and timing of electronic media use should be developed,” write the researchers.
“The current recommendation is not to have a TV in the bedroom. It seems, however, that there may be other electronic devices exerting the same negative influence on sleep, such as PCs and mobile phones. The results confirm recommendations for restricting media use in general.”
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