In the United States today, we are starting to see more and more of a problem with children who are overweight. Doctors and other health care professionals are trying to do something about it. They are recommending healthier foods and encouraging children get daily vigorous exercise. They also recommend that children go outside and play instead of sitting in front of the tv. They have suggested that children get at least an hour of exercise a day by participating in activities like jumping rope, cycling, or basketball, movement that makes the heart beat faster. This kind of exercise is known as aerobic exercise. Something else they recommend is for children to do exercises that strengthen the bones and muscles. There are a lot of ways that children can do this. One way is running.

What is the meaning of "vigorous" in the above text?