Editor,—In assessing the health benefits and risks of physical activity, there has been much interest in the relation between exercise and the immune and inflammatory responses. However, only a very limited number of studies have examined the role of exercise on adhesion molecule profiles. P-selectin (CD62P) is an adhesion molecule expressed on activated platelets and endothelial cellsand is one of a group of related molecules that play an important role in leucocyte rolling on the vascular endothelium. Therefore it is intimately involved in the regulation of immune and inflammatory responses. Circulating forms of several adhesion molecules, including P-selectin, have been observed in humans, and elevated levels may reflect acute infection …