There is now clear scientific evidence linking regular aerobic physical activity to a significant cardiovascular risk reduction, and a sedentary lifestyle is currently considered one of the five major risk factors for cardiovascular disease. In the European Union, available data seem to indicate that less than 50% of the citizens are involved in regular aerobic leisure-time and/or occupational physical activity, and that the observed increasing prevalence of obesity is associated with a sedentary lifestyle. It seems reasonable therefore to provide institutions, health services, and individuals with information able to implement effective strategies for the adoption of a physically active lifestyle and for helping people to effectively incorporate physical activity into their daily life both in the primary and the secondary prevention settings. This paper summarizes the available scientific evidence dealing with the relationship between physical activity and cardiovascular health in primary and secondary prevention, and focuses on the preventive effects of aerobic physical activity, whose health benefits have been extensively documented.