The circulatory response to exercise: Role of the peripheral pump

The circulation of blood during upright exercise involves a two-pump system , a central cardiac pump and a peripheral pump responsible for systemic ven ous return. Axiomatically, the function of the two pumps must be equal, and certain evidence suggests that the peripheral pump may "drive" the circula tion during exercise. Despite its potential importance to circulatory reser ve and aerobic fitness, little is known regarding the determinants of the p eripheral pump. Pumping function of skeletal muscle and the suction effect of the left ventricle presumably are principal factors in defining systemic venous return. This review, which focuses on data in humans, examines curr ent information regarding the peripheral pump and its potential role as a c ritical determinant of maximal cardiac output, maximal oxygen uptake, and e ndurance fitness.