We think we know everything about our bodies, but do we? We heard countless rumors as children and now we believe these myths because no one ever told us differently. For example, we actually use more than 10% of our brain, despite the rumor that we don’t. Here are five common myths about the human body that most people still believe. Do you?

You’re Not Really Double-Jointed

Do you know someone who claims to be “double-jointed”? We hate to break it to you, but there is no such thing as having double-joints. Some people are lucky enough to be born with more flexible ligaments or smaller bones that allow them to bend their joints farther than others. But no one has double-joints.

Knuckle-Cracking Doesn’t Cause Arthritis

If you crack your knuckles, someone may have once told you that this habit will cause arthritis. However, scientists say there is absolutely no evidence that knuckle-cracking causes this. In fact, the “cracking” or “popping” sound is caused by gas bubbles bursting in the fluid surrounding your joints. This action won’t cause nerve pain, but it could potentially lead to swollen hands and reduced grip strength.

Reading In The Dark Won’t Harm Your Eyes

Your parents probably scolded you for reading in the dark, telling you it would strain your eyes. If you thought that sounded fake, guess what? You were right! This act won’t cause any permanent damage to your eyes. In addition, sitting too close to the television or your computer monitor won’t cause you to go blind.

Chewing Gum Doesn’t Take Seven Years To Digest

You learned this lesson in your childhood: Don’t swallow your chewing gum. It will take seven years to digest. This one is pretty easy to debunk. Gum is chewy because it contains a synthetic rubber base that isn’t easily digestible, but that doesn’t mean your digestive tract can’t handle it. The human body is capable of passing objects up to the size of a quarter, so it can handle a small piece of chewing gum.

Your Heart Doesn’t Stop When You Sneeze

Has sneezing multiple times in a row ever made you worry about your heart’s health? “Was I technically dead for a second?” No, your heart doesn’t completely stop beating when you sneeze. What happens is that the sneeze causes an increase in your heart rate due to the fluctuations in air pressure as you inhale and exhale during the sneeze. There’s no need to worry. Your heart is just fine!