dr. amy chow, three-time olympic medalist. she is now a pediatrician at the california medical foundation. the benefits of p.e., there are so many benefits. >> it's academic performance. they are able to concentrate better. >> more discipline, too? >> right through life. >> so it raises the question. people that were overweight and out of shape but it goes beyond that. there are mental issues, too? >> exactly. they have a little bit of depression, low self-esteem. other things you can think about. obesity means high blood pressure and high cholesterol levels. >> cheryl: how does it turn out when they are adults? >> it leads to greater and greater problems. adults are dealing with heart problems and things like that. if you are obesity can occur at an earlier age. >> cheryl: i've seen people are having heart trouble now that present disposes to big problems? >> right. >> so are there some activities, i know gymnastics is good? >> right. i think any kind of activity. you need to get your heart rate up. brisk walk. jogging, bikin