Even 15 minutes vigorous daily exercise helps kids

Just 15 minutes a day of kicking around a ball or swimming might be enough to keep children from becoming obese, British and U.S. researchers said on Monday.

A study of 5,500 children who agreed to wear a motion sensor device showed that those who exercised more were less likely to be obese -- and that short bursts of intense activity seemed to be the most helpful.

Children who did 15 minutes a day of moderate exercise -- equivalent to a brisk walk -- were 50 percent less likely than inactive children to be obese, the researchers reported in the Public Library of Science journal PLoS Medicine.

"Our data suggest that higher intensity physical activity may be more important than total activity," Andy Ness of the University of Bristol and colleagues wrote. . . .

The less the children exercised, the more likely they were to be obese, the study found.

"These associations suggest even a modest increase of 15 minutes moderate and vigorous physical activity might result in an important reduction in the prevalence of overweight and obesity," the researchers wrote.