What causes varicose veins?In normal veins, valves in the vein keep blood moving forward toward the heart. With varicose veins, the valves do not function properly, allowing blood to remain in the vein. When the blood remains in the vein, the vein enlarges. The most common causes of varicose veins are: defective valves, thrombophlebitis, and pregnancy. Prolonged standing and increased pressure within the abdomen may increase the risk of developing varicose veins or worsen the veins if they are
Varicose veins are caused by our upright posture. Because we are upright the weight of our blood within the veins (especially in the back of the legs) often causes the superficial thin walled veins to fill with blood, dilate and turn into varicose veins. Normally in each of the veins in this area there are valves which prevent circulating blood (which is being pushed through the circulatory systems by the heart) from flowing backwards (as gravity acts on the column of blood pulling it downward in the leg) between each heart beat. These incompetent valves are incapable of preventing the blood from flowing backwards, down into the leg causing the dilation of the veins below. Since the veins of the leg have very thin muscular walls they rely on the tissues surrounding them to give them support and prevent dilation. The deeper the veins are the more it is supported by the tissue and muscles that surround it. On the other hand, the more superficial veins do not have as nearly as much protection. As superficial veins dilate more blood fills a given segment and since this blood weighs more the valves have to work harder to maintain protection against back flow. With time they eventually fail, the vein exceeds its capacity to function normally and varicose veins result.
Arteries carry blood from your heart to the rest of your body's tissues. Veins return blood from your body to your heart, so the blood can be recirculated. To return blood to your heart, the veins in your legs must work against gravity. This is accomplished by muscle contractions in your lower legs, which act as pumps; toned, elastic vein walls that help blood return; and tiny one-way valves in your veins. The valves open as blood flows toward your heart and close to stop blood from flowing backward.
Varicose veins occur when the valves in your veins malfunction. As you get older your veins can lose elasticity, causing them to stretch out. When that happens, blood that should be moving toward your heart may flow backward. Blood pools in your veins, and your veins enlarge and become varicose. The veins appear blue because they contain de-oxygenated blood, which is in the process of being recirculated.
Some pregnant women develop varicose veins. Pregnancy increases the volume of blood in your body but decreases the flow of blood from your legs to your pelvis. This circulatory change is designed to support the growing fetus, but it can produce an unfortunate side effect — enlarged veins in your legs. Varicose veins may surface for the first time or may worsen during late pregnancy, when your uterus exerts greater pressure on the veins in your legs. Hemorrhoids are varicose veins located in and around the anus.