Physical education has been an institution in American schools since the late 19th century, and today almost all American children are exposed to physical education classes. It has often been claimed that physical education provides important benefits to public health. The purpose of this paper is to determine if physical education increases students' physical activity levels, in the short and longer terms, and thereby provides important health benefits. We reviewed the literature to determine the amount of moderate-to-vigorous physical activity during physical education classes, as well as to determine if physical education classes increase students' overall daily physical activity, and if physical education classes provide short-term and long-term health benefits. Our conclusion is that the literature addressing the public health effects of physical education is limited. Given the significance of this issue to the future of school-based physical education, studying the short- and long-term health and fitness effects of physical education should be a high priority for future research. (Contains 4 tables.)