Children are entering a “tragic decline” from the age of just seven, with activity levels dropping long before they leave primary school, new research suggests.
Fitness experts said British pupils were entering a state of “digital dependence” which would shorten lives, with sedentary lifestyles becoming the norm long before children reached adolescence.
The Gateshead Millenium Cohort study tracked more than 500 children for eight years, with trackers measuring activity levels.
Until now, efforts to improve uptake of sport and fitness have assumed that the significant slump in activity comes with puberty, especially with girls.
But the new study shows a sharp drop in activity levels between the ages of seven and nine, among boys and girls, with a decline continuing into adolescence.
At the age of seven, the average boy was moderately or vigorously active for one hour 15 minutes a day, the study found, dropping to one hour 10 minutes by the age of nine, and just an hour by the age of 12. By the age of 15, the figure is just 51 minutes, the research shows.
Seven-year-old girls had such activity levels for 63 minutes a day, dropping to 56 minutes by the age of nine, and 47 minutes by the age of 12. At 15, the average girl is active for just 41 minutes daily, the tracking devices found.
Much of the damage was caused because of the amount of time children spent on smartphones and computers, as well as being driven to school instead of walking, experts said.
Jack Shakespeare, Head of ukactive Kids, said: “Physical inactivity is society’s silent killer and the biggest tragedy is that it’s creeping up on our children before they’ve even left the playground.”
While extra funding for school sport was welcome, he said a wider “cultural shift” was needed to protect an inactive generation from a lifetime of health problems.
“It’s not just a case on buying more bats and balls for the PE cupboard, we have to embrace creative solutions and look at how we harness our digital dependence to build movement back into children’s lives, instead of taking it away,” he said.
The study, led by the University of Strathclyde and published in the British Journal of Sports Medicine, said the findings contradicted a prevailing view among policy makers and health professionals that physical activity levels were adequate in childhood, but fell sharply during adolescence.
Researchers said there was now little evidence to back up that theory, with previous studies taking place before the advent of computer games and smartphones.
Physical activity levels were measured when the children were 7, 9, 12 and 15, using a lightweight portable monitor worn for seven days at a time.
Overall, the total volume of physical activity fell from the age of seven onwards in both boys and girls during this time, with declines no steeper during adolescence than in earlier childhood, the research found.