By promoting physical activities and incorporating them into their community-based programs, Extension professionals are improving the health of individuals, particularly those with limited resources. This article is the third in a three-part series describing the benefits of physical activity for human health: (1) biological health benefits of physical activity, (2) mental health benefits of physical activity, and (3) recommended amounts of physical activity for optimal health. Each part of the series is designed to help Extension professionals effectively integrate physical activity into community programs and motivate individuals to maintain an interest in being physically active during and after a program. [For Part 2, see EJ1092533.]