London - Nine out of 10 children are not getting enough sleep or exercise and spend too much time at screens, experts warn.
Children who spend hours on smartphones and tablets move around less, and the blue light from the devices disrupts their sleeping patterns.
The study, by Loughborough University and University College London, looked at screen time, sleep and physical activity in children based on the Millennium Cohort Study of 2015 and 2016.
The study, in journal JAMA Pediatrics, states only 9.7% of 14 year olds in the UK meet three recommendations, with more than three-quarters of teenagers spending more than two hours on screens daily.
England has no screen time guidelines, but in Canada less than two hours a day is recommended for younger children.
The results show just 23.1% of 14 year olds manage this, and the study of almost 4 000 UK children found almost 77% of 14 year olds spend two or more hours a day at screens.
Furthermore, less than half of 14 year olds manage to achieve the recommended hour or more a day of moderate or vigorous physical activity. Researchers also found more than one in 10 children failed to get more than eight hours of sleep on a school night.
Children with symptoms of depression and boys who were obese were least likely to meet the standards set.
The authors conclude: "The first step toward targeted intervention efforts is an understanding of the factors that are associated with engaging in multiple unhealthy behaviours."Daily Mail