It is thought that, of the children who stop exercising, the majority stop in adolescence, however a study in The British Journal of Sports Medicine suggests that most actually fall away around the age of seven.
The research suggests that from the time children start school they begin to spend more time sitting, and less time being active.
Experts from Glasgow and Newcastle monitored the activity levels of children over a span of eight years, using trackers worn for a week at a time.
The activity levels were measured first at the age of seven and then again at ages nine, 12 and 15.
On average, boys spent 75 minutes a day exercising when they were seven, which fell to 51 minutes by the time they were 15.
Whereas, seven-year-old girls tended to spend 63 minutes per day exercising, which dropped to 41 minutes at 15.
Only one in five of the boys studied maintained their exercise levels over the course of the study, with the majority of these being the ones with the highest activity levels when the study started. Although the study cannot prove any causes for a drop off, Prof John Reilly, study author from the University of Strathclyde, said “something is going wrong in British children” far before they reach adolescence.
The research found that seven-year-old children spent around half of their day sitting, with this raising to around three-quarters of the day by the age of 15.
“Activity tails off from around the time of going to school, when there’s a change in lifestyle,” Prof Reilly said. “Schools should be more active environments. There should be more activity breaks to break up long periods of sitting.” Eustace de Sousa, national lead for children, young people and families at Public Health England, said: “It’s a major concern that one in five children leaves primary school obese. “Most children don’t do enough physical activity, which has consequences for their health now and in the future,” he said. “It’s up to all of us to ensure children get their recommended one hour of physical activity a day.”
Mr De Sousa said this principle was at the core of the government’s childhood obesity plan, which provided extra funding for schools to get children moving and support for families to keep children active outside of school. NHS Choices says children and young people should cut back on the time they spend watching TV, playing computer games and travelling by car.