Physiotherapists should take a primary role in relation to the prevention and management of all diseases that are associated with low levels of physical activity. The benefits of regular physical activity on health, longevity, and well being easily surpass the effectiveness of any drugs or other medical treatment. Physical activity has many beneficial effects on the body, helps prevent the development of many chronic diseases and is a useful complement to drug treatment in many diseases. As the importance of physical activity for health might well be underrated and undervalued even by manual therapists we describe the physiological consequences and health dangers of being inactive in this paper.