Not exactly shocking news, from an AP article of the same title by Maria Cheng:

European and international health experts say a new study makes the most convincing case yet for the benefits of children being active. They say the research may lead to new guidelines saying youngsters between ages 5 and 16 need to be active up to 1 1/2 hours a day.

For some parents, that might be accomplished simply by showing their children the door...

The study looked at 1,732 9-year-olds and 15-year-olds from Denmark, Estonia and Portugal. Physical activity was monitored for four consecutive days by strapping little machines to the youngsters' hips, which monitored accelerations in body movements.

Despite differences among the three countries where children were monitored, the benefits of physical activity were consistent. The more active children had healthier numbers for blood pressure, cholesterol and insulin.