Disease prevention not only entails stopping the development of the disease before it occurs, but also includes measures aimed at slowing down the progression of the established disease. Diabetes mellitus should be seen as an interacting occurrence between people and their environment. Thus the primary concern in prevention and treatment of type 2 diabetes mellitus should include changes in those structural, social and economic factors that are important determinants of lifestyle. Exercise has long been a cornerstone in the management of diabetes based on its potential to improve metabolic control and diminish complications. Presently the lack of understanding pertaining to exercise and its benefits, associated with type 2 diabetes mellitus as well as the absence of education and intervention programmes makes good diabetes management difficult to achieve. Exercise is undervalued in the management of type 2 diabetes mellitus. This may be due to a lack of understanding and motivation on the part of the person with diabetes mellitus as well as the absence of clear recommendations, encouragement and follow-up actions by health-care workers. Health-care workers should address these issues because most people with type 2 diabetes mellitus have the potential to derive benefit from regular, moderate levels of exercise.