Exercise: friend or foe?

Physical activity and exercise have been associated with reduced cardiovascular risk, morbidity, and mortality, as well as all-cause mortality, both in the general population and in patients with various forms of cardiovascular disease. Increasing amounts of exercise are associated with incremental reductions in mortality, but considerable benefits have been found even with a low level of exercise. Exercise is beneficial for most individuals, but risks exist. Exercise is associated with reduced long-term morbidity and mortality, but acute exercise can transiently increase the risk of fatal or nonfatal cardiovascular events. Although tragic, these events are very rare, and even to some extent preventable with screening programmes. Low-intensity physical activity is important and beneficial to all individuals, including those with a high risk of adverse cardiovascular events. In individuals who are physically fit and who do not have genetic predisposition to, or signs of, cardiovascular disease, the greater the intensity and amount of exercise, the greater the health benefits. Nevertheless, effective strategies to encourage exercise in the population are lacking. A sustained increase in physical activity is likely to require more than individual advice, and needs to include urban planning and possibly even legislation.