The cardiovascular system is made up of the heart, veins, arteries, and capillaries. It is your body's transportation system, carrying food and oxygen to your body's cells. Your heart pumps blood through the system: oxygen-rich blood from the lungs goes out through the arteries and waste-filled blood comes back through the veins to be cleansed and recharged with oxygen. The cardiovascular system also retrieves blood from your legs and lower torso, carrying it upwards against the force of gravity. Inversion allows your body to work with gravity to ease the circulation process.
Unlike the cardiovascular system, the lymphatic system has no pump. Only the alternate contraction and relaxation of muscles moves lymphatic fluid "uphill" through capillaries and one-way valves to the upper chest for cleansing. Inverting the body so that gravity works with, not against, these one-way valves helps to push the lactic fluid up to the chest. The faster the lymphatic system is cleared the faster the ache and pain of stiff muscles disappears.