The chronic health conditions endemic in many industrialized countries now account for the "leading causes of death globally, killing more people each year than all other causes combined". Regular physical activity can reduce the risk of chronic health conditions such as cardiovascular disease, type diabetes, and selected forms of cancer, and it can also reduce the risk of osteoporosis as well as improve mental health and mood and increase longevity. The ecosystem services presented thus far have been a product of the presence of green infrastructure (GI) in the local, regional, and global environment. What we consider now is how access to GI as an environmental amenity can facilitate the health behavior of physical activity. The ability of GI to support physical activity is influenced foremost by access, which is most often measured by proximity. Once access is achieved, there are a number of other characteristics that influence its use.