[Primary and secondary prevention: physical activity].

Scientific studies aimed at elucidating the mechanisms and merits of regular physical exercise with respect to the prevention of coronary artery disease and its sequelae were undertaken relatively recently. A number of individual factors have been identified by which regular physical exercise may influence the course of coronary artery disease. Lowering of serum lipoproteins, such as low density lipoproteins und triglycerides, may retard the progression of coronary lesions. Lowering of elevated blood pressure and development of coronary collaterals may reduce stress-induced myocardial ischemia. Recently, correction of disturbed endothelial function could be shown in patients with coronary artery disease four weeks after daily physical exercise. By improving coronary vasodilation during physical stress myocardial perfusion could be increased independently from coronary morphology. In the field of primary prevention several studies comprising large numbers of patients have been conducted. Physical activity was assessed by detailed questionnaires, or physical fitness was quantitated by stress testing. For all studies a negative linear correlation was detected between the intensity of physical activity and coronary mortality. In secondary prevention the studies were considerably smaller and therefore did not reach statistical significance. By combining 22 studies in a metaanalysis, a significant negative linear correlation could be demonstrated. The recommendation of the German Society for Cardiology are based on the results of these studies; they call for regular physical exercise at intermediate or high intensity for 30 to 45 minutes on at least five days per week.