在病理學及臨床上的研究顯示，凝血系統在心血管疾病的發生及惡化的病程上扮演重要的角色。過去的研究指出，規律的運動能降低心血管疾病的發生，但劇烈急性運動反而可能誘發心因性猝死的危險。本篇論文整理並分析過去有關急性運動及運動訓練（慢性運動）對健康人及罹患心血管疾病患者之血小板功能、血液凝固反應、與血液溶纖反應影響。在我們及其他相關的研究顯示，急性運動的強度是影響血小板功能的重要因素；亦即，劇烈運動會促進血小板功能，但是中度運動反而會趨向於降低血小板的活性。並且，此急性運動的效應，在日常活動量較少者會比有規律運動者顯著。此外，如經長期規律的中等運動強度之訓練後，會降低休息時血小板功能及在急性劇烈運動所誘發血小板活性上升的程度，但此訓練效應在停止訓練後又會回復至訓練前狀態。另一方面，在一些文獻也指出，急性運動的強度與其血液凝固及溶纖活性的表現有關。這些研究結果顯示，中度運動時雖會促進體內血液溶纖活性，但並不足以造成血液凝固活性的改變；然而在劇烈運動時，不僅血液溶纖纖活性會上升外，同時也會誘發顯著血液凝固活性增加。在運動訓練效應方面，過去的研究顯示，心肌梗塞的患者在接受適當的運動復健計劃後，會降低血液凝固活性及提升血液溶纖活性。因此，從這些文獻的整理與回顧提供了為何「中等運動強度之訓練可保護個人免於心血管疾病發生，但劇烈運動反而會加速血栓形成的危險」之有利論證。

Pathological and clinical studies have suggested that blood hemostasis play an important role in the pathogenesis and progression of
cardiovascular diseases. It has also been noticed that on one hand, regular exercise can reduce the risk of cardiovascular diseases, and on the other hand, vigorous exercise provokes sudden cardiac death. This review summarizes and analyzes the literature with regard to the effects of acute exercise and endurance training (chronic exercise) on measures of plate-let function, coagulation, and fibrinolysis in healthy people and patients with cardiovascular disease. Various studies, including our previous studies, showed that the intensity of acute exercise is important factor affecting platelet function; i.e., moderate exercise tends to decrease platelet activity, whereas strenuous exercise can enhance platelet activity, and (he acute exercise effect is more pronounced in the sedentary than in the active. Moreover, platelet function may be depressed by moderate exercise training and be reversed back to pre-training states after deconditionining. Studies also have examined the relationship between exercise intensity and activation of coagulation and fibrinolysis. These results suggested that moderate exercise appears to enhance in vivo blood fribrinolysis, whereas very heavy exercise activates blood fibrinolysis and blood coagulation simultaneously. In addition, evidence is also avail- able to suggest that postmyocardial patients have lower coagulability but higher fibrinolytic activity after exercise rehabilitation programs. Therefore, these findings provide new insight into the protective effects of moderate exercise training against the risk of cardiovascular disease. However, the risk of major vascular thrombotic events may be transiently increased during vigorous exercise.