Understanding Varicose Veins: The Basics

Medically Reviewed by Stephanie S. Gardner, MD on February 21, 2024
3 min read

Varicose veins are usually bulging, bluish cords running just beneath the surface of your skin. They almost always affect legs and feet. Visible swollen and twisted veins -- sometimes surrounded by patches of flooded capillaries known as spider veins -- are considered superficial varicose veins. Although they can be painful and disfiguring, they are usually harmless. When inflamed, they become tender to the touch and can hinder circulation to the point of causing swollen anklesitchy skin, and aching in the affected limb.

Besides a surface network of veins, your legs have an interior, or deep, venous network. On rare occasions, an interior leg vein becomes varicose. Such deep varicose veins are usually not visible, but they can cause swelling or aching throughout the leg and may be sites where blood clots can form.

Varicose veins are a relatively common condition, and for many people they are a family trait. Women are at least twice as likely as men to develop them. In the U.S. alone, they affect about 23% of adult Americans.

To help circulate oxygen-rich blood from the lungs to all parts of the body, your arteries have thick layers of muscle or elastic tissue. To push blood back to your heart, your veins rely mainly on surrounding muscles and a network of one-way valves. As blood flows through a vein, the cup-like valves open to allow blood through, then close to prevent backflow.

In varicose veins, the valves do not work properly, allowing blood to pool in the vein and making it difficult for the muscles to push the blood "uphill." Instead of flowing from one valve to the next, the blood continues to pool in the vein, increasing venous pressure and the likelihood of congestion while causing the vein to bulge and twist. Because superficial veins have less muscle support than deep veins, they are more likely to become varicose.

Any condition that puts excessive pressure on the legs or abdomen can lead to varicose veins. The most common pressure inducers are pregnancy, obesity, and standing for long periods. Chronic constipation and -- in rare cases, tumors -- also can cause varicose veins. Being sedentary also may contribute to varicosity because muscles that are out of condition offer poor blood-pumping action.

The likelihood of varicosity also increases as veins weaken with age. A previous leg injury may damage the valves in a vein, which can result in a varicosity. Genetics also plays a role, so if other family members have varicose veins, there is a greater chance you will, too. Contrary to popular belief, sitting with crossed legs will not cause varicose veins, although it can aggravate an existing condition.

Even though your genetics play a part in your risk for varicose veins, there are things you can do to prevent them.

  • Exercise regularly. Staying fit is the best way to keep your leg muscles toned, your blood flowing, and your weight under control.
  • Maintain a healthy weight. If you are overweight or obese, lose weight. Weight control prevents excess pressure buildup on veins of the legs and feet.
  • Avoid tight clothing. Tight clothes can constrict blood flow in the waste, groin, or legs.
  • Avoid high heel shoes.  Wearing high heels for prolonged periods of time can hinder circulation. Flat or low-heel shoes are better for circulation, as they improve calf muscle tone.
  • Move around. Avoid sitting or standing for prolonged periods of time to encourage blood flow. If your daily routine requires you to be on your feet constantly, consider wearing daily support hose. Stretch and exercise your legs as often as possible to increase circulation and reduce pressure buildup.
  • Quit smoking. Studies show that smoking may contribute to the development of varicose veins.
  • If you're pregnant, sleep on your left side rather than your back.  This will minimize pressure from the uterus on the veins in your pelvic area. This position will also improve blood flow to the fetus. If you are prone to developing varicose veins, ask your doctor for a prescription for compression stockings.