"Physical activity," "exercise," and "physical fitness," are terms that describe different concepts. However, they are often confused with one another. This paper proposes definitions to distinguish them.
Any bodily movement that is produced by skeletal muscle and that substantially increase energy expenditure.
Any bodily movement produced by the contraction of skeletal muscle that increases energy expenditure above a basal level. In these Guidelines, physical activity generally refers to the subset of physical activity that enhances health.
Any form of exercise or movement.