Screens produce a bright light, which can stop the body producing melatonin - the sleep hormone - which is produced naturally as the evening becomes darker.

London - Children who bask in the night-time glow of a TV or computer don’t get enough rest and suffer from poor lifestyle habits, new research from the University of Alberta has shown.

Researchers found that children with one or more electronic devices in the bedroom, TVs, computers, video games and cellphones, were far more likely to be overweight or obese.

“If you want your kids to sleep better and live a healthier lifestyle, get the technology out of the bedroom,” said co-author Professor Paul Veugelers.

Veugelers, director of the Population Health Intervention Research Unit, said the research was the first to connect the dots on the relationship between sleep, diet and physical activity among kids.

Nearly 3 400 Grade 5 students aged 9-11 were asked about their sleep habits and access to electronics through the REAL Kids Alberta survey. Half of the students had a TV, DVD player or videogame console in their bedroom, 21 percent had a computer and 17 percent had a cellphone.

Five percent of students had all three types of device.

Fifty-seven per cent of students reported using electronics after they were supposed to be asleep, with watching TV and movies being the most popular.

Twenty-seven percent of students engaged in three or more activities after bedtime.

Researchers found that students with access to one electronic device were 1.47 times as likely to be overweight as kids with no devices.

That increased to 2.57 times for kids with three devices, with similar results reported among obese children.

More sleep also led to significantly more physical activity and better diet choices, researchers found.

Co-author Christina Fung noted that children today are not sleeping as much as previous generations, with two-thirds not getting the recommended hours of sleep.

In addition to healthy lifestyle habits, a good night’s sleep has been linked to better academic outcomes, fewer mood disorders and other positive health outcomes, she said.

“It’s important to teach these children at an earlier age and teach them healthy habits when they are younger.” – Daily Mail