Abstract
Epidemiologic studies have consistently identified a strong inverse association between coronary heart disease (CHD) and regular, predominantly moderate-intensity physical activity and cardiorespiratory fitness. Supporting evidence of causative relationships has been provided by aerobic exercise training studies in both animals and humans. This research demonstrated multiple plausible cardioprotective biological mechanisms. These include direct antiatherosclerotic effects by improving artery endothelial function and reducing inflammation and indirectly via modification of other risk factor components of the metabolic syndrome, by reducing risk of a coronary thrombotic occlusion (antithrombotic effects), by decreasing myocardial oxygen demands and increasing its vascular supply (anti-ischemic effects), and by improving cardiomyocyte electrical stability and autonomic nervous system adaptations (antiarrhythmic effects). Although much additional research is needed to better define and establish optimal dose-response relationships, clearly these pleotropic effects strongly suggest that aerobic exercise can attenuate the risk of CHD at all stages of the underlying atherothrombotic process.