Physical activity levels may start tailing off as early as seven-years-old, rather than during teenage years as is widely believed, new research reveals.
Scientists at Newcastle University and the University of Strathclyde carried out research which questioned the assumption that decline only happens among teens and is gender specific.
There is no evidence to indicate that the decline is greater among girls than it is among boys, the results show.
Researchers say there is an assumption among policy makers and health professionals that physical activity levels during childhood are adequate, but fall sharply during adolescence, and that the decline is significantly greater among girls.
But there is little hard evidence to back this up, and what research has been carried out in this area has mostly been done before the impact of new technologies would have been felt, the experts add.
Professor Ashley Adamson, of Newcastle University’s Human Nutrition Research Centre, is a co-author of the paper. She said:
In a bid to quantify the timing of any changes, experts tracked the physical activity levels of a representative sample of around 400 children taking part in the Gateshead Millennium Cohort Study from 2006 to 2015.
Physical activity levels were measured when the children were seven, nine, 12 and 15, using a small lightweight portable monitor, worn for seven days at a time.
The monitor - known as an actigraph - recorded activity for 15 second intervals, and was removed only at night, and for bathing/swimming.
As an additional back-up, the families involved were asked to log when the devices were worn and removed each day.
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. But the decline was not uniform, the data showed.
Four distinct patterns emerged for the boys:
There were three different patterns among the girls:
This is an observational study, so no firm conclusions can be drawn about cause and effect, added to which, although representative of North East England, the study findings may not be applicable to other areas of the country, or other nations, say the researchers.
The findings have been published online in the British Journal of Sports Medicine.