Maybe you've seen them before: blue or purple squiggles on grown-ups' legs that look like lines on a roadmap. And maybe you thought, "What the heck are those?" Well, they're veins.

But wait a second — why don't you have them? And why do they look different from the veins on the inside of your wrist or elbow? That's because those grown-up veins are varicose (say: VAIR-uh-kose) veins.

Blood Vessel Basics

What is a varicose vein, anyway? It's a vein that has become stretched and swollen with blood. To understand how that happens, let's learn a bit about what veins do.

You have veins and arteries running through your whole body. They are tiny tubes that carry blood to and from every part of your body, from your nose down to your toes. The flow of blood starts with the pumping action of your heart. When your heart beats, it pumps your blood and moves it through all those little tubes. The arteries carry the blood from your heart out to your body, and the veins carry the blood from your body back to your heart.

The blood going out to your body in the arteries is full of oxygen, which makes the blood bright red. But the blood coming back from your body in the veins is darker because your body parts have used up the oxygen in the blood. That's why veins look purple or blue.

What Causes Varicose Veins?

It's a lot of work to move all that blood. To do their job, veins are full of valves that help keep the blood flowing in the right direction. Valves are like tiny doors that close after the blood has passed through to keep blood moving along and to make sure it doesn't flow backward.

As people get older, though, the valves might not work as well. When that happens, some blood can stay in a vein instead of moving forward like it should. This makes the vein swell, and that swollen vein is a varicose vein.

The veins often show up on the legs, ankles, and feet because those body parts are farthest from the heart. Gravity pulls blood down into your legs and feet when you're standing up or sitting down. So the veins have to work extra hard to get that blood back up to the heart, and some of those veins can wear out over time.

Varicose veins look twisted and purple or blue, and they're raised, which means they look like they're sitting on top of the skin. They can be tender and painful, especially after sitting or standing still for a long time. People who have varicose veins might also have achy legs that feel heavy.

Who Gets Them?

Varicose veins are more common in women. People are more likely to get them as they get older. These veins can be genetic (say: juh-NEH-tik). That means that if your mom or your sister has them, you might get them. Things that put pressure on your legs and feet — like being overweight or standing for a long time every day without exercise — can also cause varicose veins. Sometimes women who are pregnant get them too.

If someone you know has varicose veins, it's really no big deal. They're usually pretty harmless. But people who have problems like pain with their varicose veins will sometimes see a doctor to have them removed.

To get rid of varicose veins, some of the things doctors can do is zap them with light from a special laser or use something called sclerotherapy (say: skler-OH-thair-uh-pee). In sclerotherapy, the doctor injects fluid into the vein that makes it shrivel up. Both of these treatments are pretty common.

Luckily, you can do things now so you're less likely to have varicose veins when you're older. First, get your blood moving with regular exercise. Keeping your body fit helps keep your veins fit too! Also, don't put a lot of pressure on your legs and feet by standing or sitting for too long without moving around. Help keep your blood flowing and your body will love you for it!