AARP Eye Center
If you swallow gum, it will sit in your body for seven years before you can digest it. When a jellyfish stings you, the first thing you should do is pee on the injury to neutralize the sting. And sitting too close to the TV can ruin your eyes!
At some point in your life, you’ve probably heard these statements and others like them. Your parents may have even used them when you were a child to get you to do something healthy, like take a break from watching TV. Many of these old wives’ tales have been with us for centuries. But is there any merit to them, or are they merely stories passed down from generation to generation? We asked several experts to weigh in on whether you need to worry about the nine commonly heard statements below.

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1. Cracking your knuckles causes arthritis
“Cracking your knuckles will not cause arthritis,” explains Howard Luks, an orthopedic surgeon in New York and the author of Longevity … Simplified.
While there are a few published stories of injuries — and there’s research suggesting that people who crack their knuckles may have more hand swelling and less grip strength than those who don’t — Luks says there is nothing wrong with cracking your knuckles gently and on rare occasions. The most recent studies have found that even habitual knuckle crackers are not at an increased risk of being diagnosed with osteoarthritis.
Curious about what causes that pop you hear when you crack your knuckles?
“Our knuckles make that sound because of negative pressure within our joint, which causes a popping when the lubricating fluid — synovial fluid — produces pockets of bubbles,” says Luks. It’s noisy but it’s not going to set you up for a future of joint pain.
2. Hair of the dog gets rid of a hangover
Ever drink too many beers, wake up with a hangover and have a friend tell you that drinking another beer with breakfast could help? You might feel better initially, but that won’t last for long, says Jeffrey Linder, chief of general internal medicine at Northwestern University Feinberg School of Medicine. “You’re just prolonging the hangover,” he explains. “If you’re hungover, you poisoned your body,” he adds. “And giving yourself more of a poison might make you feel a little bit better for a second, but it doesn’t seem like a great idea.”
Common hangover symptoms include headaches, nausea, muscle aches, sensitivity to light and sound, and thirst. The latter is not helped by consuming more alcohol because it’s a diuretic, which causes increased urination and an excessive loss of fluids. So instead of reaching for another beer or shot of vodka the morning after, Linder says you’re much better off grabbing some water and focusing on rehydrating yourself. And if you are suffering hangovers regularly, you might consider a dry January (or February or March).
3. Gargling with salt water cures a sore throat
“Salt water is a soothing solution that balances with the fluid in the back of your throat and the mucous membranes there,” Linder explains. “We recommend this all the time for people who have sore throats.” He suggests mixing a couple of tablespoons of salt in a moderate to large glass of water — preferably warm, which is closer to your body temperature and more soothing — and gargling that at the first sign of a sore throat.
Some studies have even found gargling to be a preventive measure that helps ward off colds or flus. One study found that water gargling decreased how likely someone was to catch an upper respiratory tract infection by 36 percent within the first 60 days of cold and flu season.