Figure 1: Schematic relationship of Muscle Atropy affecting the determinants of Venous Return. Briefly: Muscle atrophy causes venous blood pooling which favors an increase in the unstressed volume and a decrease the stressed volume. As a result, the mean circulatory filling pressure decreases producing a reduction in right atrium filling and leads to extensive physical deconditioning, indicated through, e.g., the reduced demand of oxygen to the muscle leading to vascular atrophy. This compensatory mechanism will increase vascular resistance and contribute to a reduction in venous return. In the absence of skeletal muscle venous pumps, these hemodynamic changes promote an abnormal venous return that could compromise stroke volume and cardiac output.