[Cardiorespiratory fitness. Importance of sports for health]

Abstract

Epidemiologic studies have established that physical activity is associated with substantial improvements in cardiovascular prognosis. The effect of physical activity appears to be in the order of traditional risk factors such as smoking or hypercholesterolemia. The strength of evidence is best for intensive activity, corresponding to an energy expenditure > 6 METs (metabolic equivalent). Cardiorespiratory fitness can be determined directly by using treadmill- or bicycle-based exercise stress testing. Exercise stress testing in healthy subjects shows that in the lowest quintile of fitness distribution, cardiovascular morbidity and mortality are greatly increased. Prognosis improves significantly when reaching a higher level of fitness (better than the worst 20%). Physical activity exerts beneficial effects on cardiovascular risk factors and on subclinical atherosclerosis (e. g., endothelial function, progression of atherosclerotic plaques), and it reduces cardiovascular endpoints. An increase in cardiorespiratory fitness by 1 MET brings along a risk reduction of approximately 20%. Physical exertion itself is associated with an increased risk of sudden cardiac death, which is alleviated, however, by regular training. All in all, the risk-benefit relation is very favorable and better than for most other interventions.