How do you like to sit when you’re at the office? How about the dinner table? The bus? Many people are most comfortable sitting with one leg crossed over the other. Sure, your foot may go numb from time to time, but it’s comfortable and it works for you. But is it doing you more harm than good?

People have long believed that crossing your legs while sitting is bad for you. It’s said to cause varicose veins, birth complications for pregnant women, and high blood pressure. Keep reading to learn what science says about each of these claims.

During pregnancy, the body goes through a variety of physical changes. As your uterus stretches, your center of gravity shifts forward. You may find yourself walking, standing, and sitting differently than you usually do.

While you might find yourself sitting in new positions as you try to get comfortable, none of them will hurt you or your baby — including sitting with crossed legs.

That said, muscles strains, backaches, and cramps are all common during pregnancy. While sitting with your legs crossed won’t hurt your baby, it may contribute to ankle swelling or leg cramps. If you find your ankles swelling or your legs cramping, try sitting with both feet on the floor or elevated on a stool.

When you get your blood pressure tested, you’re usually asked to place both feet on the ground. This is because crossing one of your legs over the other can cause a temporary spike in blood pressure.

A study published in the Journal of Clinical Nursing found a significant increase in blood pressure when participants crossed their legs at the knee level. There was no spike when legs were crossed at the ankle.

Another study, published in the Journal of Hypertension, found a slightly bigger spike in blood pressure when participants crossed their legs by putting their ankle on their knee.

While these studies support the claim that crossing your legs can raise your blood pressure, they only showed a temporary increase. However, if you already have high blood pressure, try to avoid spending long periods of time with your legs crossed just to be safe.

For many years, rumors have circulated that crossing your legs can cause varicose veins. This is a myth.

Varicose veins are those bulging, twisting, cord-like veins that pop out of your legs. While they’re often blue, they can also be red or flesh-colored. They’re usually found on the thighs, backs of the calves, and inner leg. Anyone can get varicose veins, but they tend to be more common in older women and pregnant women.

Varicose veins form because of a problem with the valves in your veins, which work very hard to pump blood up toward the heart. As the blood moves upward, one-way valves open and close, preventing blood from leaking back down.

When these valves are weakened or damaged, however, the force of gravity pulls blood back down. This is known as venous insufficiency. Veins become varicose when that blood gets backed up, collects, and causes bulging.

Both standing and sitting for very long periods of time may increase your risk of developing varicose veins, but there’s no evidence that crossing your legs has this effect. If you’re concerned about developing varicose veins, try to change the position of your legs throughout the day.

While most of the common myths about sitting with your legs crossed aren’t entirely true, there is one possible side effect that’s often ignored — poor posture.

Sitting for long periods of time with your leg over your knee can cause your pelvis to rotate and tilt. This can cause pain in the lower back. It could also lead to a misalignment of your spine over time.

When you have improper posture, your muscles are forced to compensate. This means they work harder then they need to, which can lead to pain and stiffness.

Still, this doesn’t mean you need to stop crossing your legs completely. Learn more about the best postures for sitting.

Sitting with your legs crossed won’t cause a medical emergency. However, it can cause a temporary increase in your blood pressure and lead to poor posture. For optimum health, try to avoid sitting in any one position, whether you cross your legs or not, for long periods of time.