Veins carry blood back to the heart to be oxygenated, carrying that blood through valves. When those valves don't function properly, venous disease can develop. Ronald Dalman, MD, explains signs, risk factors, and treatments for venous disease available at Stanford Hospital.

One type of venous disease is varicose veins, which affect women disproportionately. According to Dalman, an estimated 40 percent of women will have chronically significant varicose veins by the time they reach 50.

Another type is Deep Vein Thrombosis, or DVT, where blood begins to pool and clot in the lower extremities. Often treated with blood thinners, DVT can be serious as there is a greater risk that a clot can break off and travel to other areas of the body, including the lungs where it may cause problems breathing or heart function.