In brief: The reasons people say they exercise are to feel better, to have a beautiful body, to socialize, and to be more healthy. People see a lack of free time as the main obstacle to physical activity. However, data from three surveys show that the need is not for more time but for using time that is already available. The author concludes that participants need a carefully tailored system of incentives and rewards to sustain the exercise habit until the intrinsic rewards of fitness become obvious.