Background: Platelets play an important role in cardiovascular disease: First, they promote the development of atherosclerotic lesions, and second, platelets form vessel occluding thrombi on top of (ruptured) lesions, ultimately leading to thrombotic events like myocardial infarctions (MCI). Whereas acute, strenuous exercise causes platelet activation and transiently increases the risk for MCIs, long-term chronic exercise training results in a clear reduction of both platelet activation and MCI incidence.