Exposure to high altitudes and exercise alters body's physiology and may cause acute cardiovascular events. Platelet activation is one of the key players in these events. Therefore, we investigated the effect of vigorous exercise at higher altitude (2650 m) on platelet aggregation and serum markers of platelet activation. 14 healthy subjects performed a step incremental ergometer test until exhaustion at the Environmental Research Station (UFS, 2650 m) at Zugspitze. Platelet aggregation and serum levels of endothelin-1, soluble p-selectin, platelet factor 4 and Chromogranin A were measured. Platelet activation was significantly enhanced after exercise at high altitude compared to measures immediately prior exercise. We detected significantly enhanced serum levels of endothelin-1 and soluble p-selectin whereas chromogranin A and platelet factor 4 remained unchanged. This effect might be due to increased endothelin-1 levels causing pulmonary vasoconstriction, rheological changes and direct platelet activation. This might be of clinical relevance, especially in patients with pre-existing diseases.

Deutsches Zentrum für Herz Kreislauf Forschung E 5 Munich Germany

Institute of Cardiovascular Physiology and Pathophysiology Biomedical Center LudwigMaximilians University Munich Planegg Martinsried Germany

Medizinische Klinik und Poliklinik 1 University Hospital Munich Campus Grosshadern and Innenstadt Ludwig Maximilians University Munich Munich Germany

Walter Brendel Centre of Experimental Medicine Ludwig Maximilians University Munich Munich Germany

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