When blood is pumped from the heart, it travels throughout the body by way of the arteries and returns through an intricate system of veins and lymph vessels.
Cardiac disease threatens circulation by crippling the ability of the heart to be an efficient pump.
Non-cardiac or peripheral vascular disease is also a threat to the circulation because it undermines the ability of the arteries and veins to transport the blood. As the country's population ages, vascular disease has become more common because vascular disorders develop over time, as arteries begin to narrow they constrict the flow of blood. This may lead to atherosclerosis or arterial disease, which may have serious and even fatal consequences if left untreated. A blocked artery to the brain, for example, may result in a stroke. Several million Americans, usually over the age of 50, are affected by peripheral vascular disease.