Health library

Health wisdom or hoax?

Learn the truth about some common health claims

Have you ever heard that you'll catch cold if you go outside with a wet head? Or that sitting too close to the TV will ruin your eyesight? If so, you may have found yourself wondering—is that really true?

Keep scrolling to learn the truth about those two health claims as well as the facts about other commonly repeated bits of health advice.

THE CLAIM: CRACKING YOUR KNUCKLES CAUSES ARTHRITIS

The facts: When you crack your knuckles, pressure changes inside the joints, causing the lubricating fluid to form bubbles that pop. While this noise may sound harmful to your joints, it doesn't cause arthritis—although there have been conflicting findings about whether knuckle-cracking reduces grip strength.

THE CLAIM: SITTING TOO CLOSE TO THE TV WILL HURT YOUR EYES

The facts: A lot of children (and some grownups) sit close to the TV, but there's no evidence that doing so hurts their vision. Sitting close to a TV may make the eyes feel strained and tired, though. It also might indicate the need for glasses or a stronger lens prescription.

THE CLAIM: SWALLOWED GUM TAKES YEARS TO DIGEST

The facts: If you swallow gum, your body won't digest it. It also won't hold on to it. Swallowed gum usually passes through the digestive tract within a few hours to a few days.

THE CLAIM: YOU SHOULDN'T SWIM FOR AN HOUR AFTER EATING

The facts: When you eat, blood is diverted to the digestive tract. This might cause less blood to flow to your muscles, but it won't prevent you from using your muscles to swim safely. But while swimming after eating is safe, it might not always be enjoyable, since large meals can leave you feeling tired and bloated.

THE CLAIM: YOU'LL GET SICK IF YOU GO OUT IN THE COLD WITH WET HAIR

The facts: Viruses, not cold weather, cause colds. So having wet hair when it's cold out won't give you a cold. However, if you already have a cold, being chilled might make your illness last longer. That's because your body works harder to stay warm in cold weather. That extra stress might weaken your immune system just enough to prolong your illness.

THE CLAIM: RUNNING WILL DAMAGE YOUR KNEES

The facts: For most runners, their activity may help protect against knee problems, such as arthritis, by strengthening the muscles that support the knee joints. Still, you may want to discuss your exercise plans with your doctor, especially if you already have a knee problem. Once you get the OK, start slowly and pay attention to how your knees feel when you run.

Explore more myths and misconceptions

Check out the claims and the truth about:

EXERCISE

MIGRAINES

IMAGING AND RADIATION

HIP REPLACEMENT