As you all know, the study work is heavy in high school. There are often more than 10 courses a day including the evening. That will take more than 9 hours in study a day, and without weekends. The students in high school are exhausted after school and not willing to do the physical exercises anymore. In fact, it is not only very bad for health but also bad for study. The teenagers have to do enough exercises to keep healthy and growing tall. And doing physical exercises can make a people strong and lighten one up, refill the energy to study more efficiently. So, the high school students should do physical exercises. They can do some sports, such as playing football or basketball, running, swimming and so on.