US Government experts recommend 60 minutes of moderate exercise most days of the week for kids and teens. In addition, you should do some sort of strength training at least twice a week.

What do you mean by, 'moderate?'

Moderate exercise means you do an activity vigorously enough to significantly increase your heart rate and breathing for an hour, which is called "aerobic exercise." This kind of exercise trains your heart and lungs to become stronger. How hard should you exercise? Some people like to follow the talk/sing rule, which says that you should be able to talk to someone while you exercise, but you should not be working so lightly that you can sing.

Another way to know if you are exercising hard enough is to calculate your Target Heart Rate range. By keeping your heart rate within the correct training range for your age, you can be sure you're getting all the benefits of aerobic exercise.