School is where adolescents get most of their exercise, but it's not enough

Even though adolescents spend less than 5 percent of their time at school engaging in physical activity, according to a new study, this time accounts for almost half of their overall exercise.

The study found that adolescents averaged 39 minutes per day of moderate-to-vigorous physical activity across all locations, which placed them among the estimated 92 percent of U.S. youths who don't get the 60 minutes of daily exercise recommended for healthy development and obesity prevention.

More than 42 percent of the children's overall physical activity took place at school, but it represented just 4.8 percent of their time there. Children were much more likely to be active when they were outdoors near their homes or schools, but they did not spend a lot of time outside in their neighborhood.