Walking exercise is the most effective medical intervention for improving walking impairment in people with intermittent claudication due to peripheral artery disease (PAD). Both supervised walking exercise and home-based walking exercise are highly effective therapies, and both are now recommended as first-line therapy to improve walking distance in people with claudication. The most effective home-based walking exercise programs include behavioral methods, such as regular contact with a coach, goal setting, and self-monitoring. While several biologic pathways by which walking exercise improves walking performance have been suggested, no definitive evidence exists.