A University of Otago study has found that the negative impact of screen time on teenagers' sleep occurs more when screens are used, especially in bed, rather than just before bed. Dr Bradley Brosnan stressed the need for updated sleep guidelines that align with modern behaviour, as screen use in bed delays sleep onset and reduces sleep duration more significantly than screen use before bed.
Current sleep guidelines recommend no screen use an hour or two before bed. However, researchers found that two hours of screen time before bed had little impact on teen sleep, while screen use once in bed caused problems.
Lead author Dr. Bradley Brosnan, of the Edgar Center for Diabetes and Obesity Research, said screen time is a staple of teenagers' bedtime habits and sleep guidelines need to be re-evaluated to better reflect modern life.
The study, published in the journal JAMA Pediatrics, looked at 85 teenagers aged 11 to 14 who wore body cameras on their chests from three hours before going to bed for a week.
In addition to the body cameras recording when, what and how they used screens, a second infrared camera was placed in their bedrooms to record their screen time in bed. They also wore actigraphs, a watch-sized device that measures sleep.
"It quickly became clear that teenagers were spending a lot of screen time in bed," Dr. Brosnan said.
Researchers found that 99% of participants used screens within two hours of bedtime, more than half used screens once in bed, and a third used screens at night after first trying to fall asleep.
"Our most interesting finding was that screen time before they went to bed had little impact on their sleep that night. However, screen time once in bed affected their sleep - keeping them awake for about half an hour and reducing their sleep time that night."
This is especially true for more interactive screen activities like gaming and multitasking, when using multiple devices at the same time, such as watching a movie on Netflix on your laptop while playing Xbox on your gaming device.
"For every 10 minutes of this increase in screen time, their sleep time that night decreased by almost the same amount. Our results suggest that the effect of screen time on sleep is primarily through delayed sleep onset via time shift, rather than any direct effect of blue light or interactive engagement, as we did not find an association between sleep latency and arousal during sleep."
Dr. Brosnan said a "simple" sleep guideline - in theory but not necessarily in reality - would be to keep devices outside the bedroom and allow teens to use them at bedtime, but not in bed.
"We need to revisit sleep guidelines so that they fit the world we live in and are truly meaningful, and current guidelines are unachievable or inappropriate for the way we live."
Compiled from /ScitechDaily