New Thinking on Old Advice
Updated health wisdom
We might have to burst your bubble on a few longstanding health tropes. Here’s the real story on four you’ve heard (and maybe said!), and what you need to know to keep your family safe and well.
1 “Don’t go outside with wet hair, or you’ll catch a cold”
You catch a cold when you are infected by a virus, not because you are cold, explains Sindhu Aderson, M.D., a family medicine doctor at Northwestern Memorial Hospital. Having wet hair won’t make that virus appear out of nowhere or even make you more likely to succumb to one that you’re exposed to. Underdressing in cold temps is a problem, however, when it comes to frostbite and hypothermia.
2 “It takes seven years to digest a piece of gum”
Don’t worry, a swallowed gumball isn’t going to sit in your child’s stomach for years, says Carolyn Newberry, M.D., a gastroenterologist at NewYorkPresbyterian and Weill Cornell Medicine. Gum moves into the stomach, goes through the small intestine and colon, and gets excreted in your poop, just like other foods, she explains. “It may stay whole during the process, though, because gum is resistant to digestive enzymes.” (For the record, the journey takes about two to three days for all food.) While an occasional swallowed piece of gum is usually harmless, an excessive amount may cause blockages. Parents should also be wary of giving gum to small children, as it’s a choking hazard, she adds.
3 “Cracking your knuckles causes arthritis”
Studies designed to see if there’s a connection between knuckle cracking and arthritis have found no link, says Stanford Shoor, M.D., a rheumatologist at Stanford Health Care. Sometimes the rubbing of the bones of the knuckle joint against one another causes small bubbles to form in the fluid that lubricates the joints. People “crack” their knuckles to pop the bubbles and relieve the pressure. The practice is relatively harmless, although one study suggests that it may reduce grip strength and in very rare cases might have been responsible for ligament damage that improved with treatment.
4 “Sitting close to the TV can make you go blind”
Sitting too close can cause eyestrain (when eyes get itchy, sore, or watery). But eyestrain, while uncomfortable, is usually temporary and isn’t linked with longterm complications. Plus, it’s less of a concern for kids than adults, as they tend to be better at focusing on things closeup. Better advice, says Joseph Panarelli, M.D., an ophthalmologist at New York University Langone Health: Children should spend less time using handheld screens, as this may potentially lead to nearsightedness.