Researchers comparing fitness levels of children today and 10 years ago in an area with low levels of obesity found that the average 10-year-old in 1998 could beat 95 per cent of youngsters in 2008 in running tests.
Essex University staged fitness tests on 600 10-year-olds a decade apart in Chelmsford, an affluent town with traditionally low levels of obesity, to illustrate how being a normal weight did not necessarily equate to having good fitness.
In 1998, they carried out 20m shuttle-run tests - commonly known as the bleep test - on 303 children from six schools. In 2008, the tests were repeated on a similar number of 10-year-olds, the Archives of Disease in Childhood reported.
Significant shift in fitness levels
While obesity levels had hardly changed, there was a significant shift in fitness which was "large and worrying". Researchers added that similar - if not worse - findings would be expected in areas with high levels of obesity.
The researchers said the focus on obesity in schools was obscuring the health risks of wider declines in fitness levels.
Activity as important as healthy diet
“Physical activity is equally as important as eating a healthy balanced diet when it comes to preventing obesity and the development of Type 2 diabetes," said Cathy Moulton, Care Advisor at Diabetes UK.
“Diabetes UK backs the Government’s recommendation that children should do 60 minutes of physical activity every day.”