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The Truth Behind 19 Old Wives’ Tales About Your Health

From gum to spiders to hangovers, here’s how to separate fact from fiction

spinner image cartoon of health situations such as chest pains, nasal congestion, drinking water, runners knee
Courtesy Remie Geofroi

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 19 commonly heard statements below.

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1. Cracking your knuckles causes arthritis

What science shows: “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. Coffee dehydrates you

What science shows: Caffeine is a mild diuretic, meaning it can stimulate your body to produce extra urine. However, research shows the liquid in coffee counteracts any dehydration effects. One study published in the American Journal of Clinical Nutrition found that people urinate the same amount whether they drink coffee, soda, tea, a sports drink or water.

3. Hair of the dog gets rid of a hangover

What science shows: 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).

4. CPR requires mouth-to-mouth contact

What science shows: Studies of adults who experienced cardiac arrest outside a hospital found that cardiopulmonary resuscitation involving only chest compressions given by rescuers who weren’t medical professionals is just as effective as — if not more effective than — CPR administered with rescue breathing, says Ahamed Idris, an emergency medicine physician.

5. Gargling with salt water cures a sore throat

What science shows: “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 with that at the first sign of a sore throat.


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Some studies have even found gargling to be a preventive measure that helps ward off colds or flu. 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.

6. Sitting too close to the TV will make your eyesight worse

What science shows: If you’re a TV binger and like to sit close to the screen, rest assured: Doing so will not make your eyesight worse. “It can cause eye strain and fatigue, as well as dry-eye issues from reduced blink rates, but it will not worsen your prescription,” says Cynthia D’Auria, director of the optometric and contact lens service at Tufts Medical Center.

However, D’Auria says it’s important to prioritize ocular health, so it’s a good idea to back up when sitting near the television to reduce strain and fatigue. If you find yourself needing to inch closer to the television than normal, it may be time to see your eye doctor, as this may be a sign that your eyesight is deteriorating and you could benefit from a new or adjusted prescription. Also, make sure to give yourself breaks from screen time in general, as research shows that tear production significantly decreased in ultra-high-definition TV watchers. In the same study, people over the age of 50 and those with dry-eye syndrome reported having more ocular discomfort after watching television.

7. Spicy foods can cause ulcers

What science shows: You ordered your Thai food hot, which for the average American can be asking for trouble. Are you in danger of triggering an ulcer? The answer is no — although you might burn your mouth a little.

“Spicy foods can make gastritis worse, but the most common cause of ulcers is actually a bacterial infection,” says Linder. Unless you are going into a meal with preexisting digestive upset, spiciness is not likely to be an issue. But if you already have an inflamed stomach, a condition like irritable bowel syndrome or an existing ulcer, eating spicy food could make you feel worse, Linder suggests.

In addition to bacteria, most commonly H. pylori, long-term use of nonsteroidal anti-inflammatory drugs (NSAIDs) like aspirin and ibuprofen (Advil) has been linked to peptic ulcer disease. (We also used to think that stress causes ulcers, but that’s not true either, according to the National Institutes of Health.)

Interestingly, 2006 research found that chile pepper may potentially be beneficial for your gut by increasing blood flow to the gastrointestinal (GI) tract to protect it. And spicy foods seem to come with benefits. One study found that people who eat spicy foods six to seven times a week had a 14 percent reduced mortality rate. So you can keep eating your food hot — as long as you’re OK with getting a little sweaty at the dinner table.

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8. Everyone should take a daily multivitamin

What science shows: A 2022 review of 84 studies by the U.S. Preventive Services Task Force found no convincing evidence that multivitamins have any benefit for nonpregnant adults. “You’ll get much more bang for your buck if you eat a healthful diet with plenty of fruits and different vegetables,” says Linder.

9. We eat eight spiders a year in our sleep

What science shows: If you were a nighttime mouth breather as a child, you probably heard one old wives’ tale that was enough to scare you into becoming a nasal breather: Humans swallow an average of eight spiders while sleeping each year. Yikes!

Fortunately, this is not likely for several reasons. “Spiders like to stay in their webs and, unless they view you as prey, aren’t going to crawl into bed,” says Joe Alton, author of The Survival Medicine Handbook: The Essential Guide for When Help Is Not on the Way. “That would have to be a pretty big spider,” he adds. If you have bedbugs, spiders might come down to your bed to chomp on those, getting near you in the process, but if that’s the case, Alton says you have bigger problems than the possibility of swallowing a spider!

Next, even when asleep, our bodies produce noise or vibrations that spiders don’t like. “Things like a beating heart, breathing or snoring all cause a spider’s spidey sense to say, ‘Stay away!’ ” explains Alton. And lastly, our lips contain sensory nerve fibers, so it’s unlikely we wouldn’t feel a spider crawling on them in the night, even if we’re deep sleepers.

The bottom line? “Swallowing a spider would be a very, very rare event, not something that occurs as often as eight times a year — and probably not eight times in a lifetime,” Alton confirms, reassuringly.

10. If swallowed, gum takes seven years to digest

What science shows: Most of us don’t make a habit of swallowing gum, but every now and then, it can happen. We grew up hearing that if you ingest gum, your body basically can’t digest it. So, if you accidentally swallow some gum, is it true that your digestive system will take a hit? Fortunately, no. “It is certainly not true that gum takes years to pass through the stomach,” says Andrew Boxer, a gastroenterologist with Gastroenterology Associates of New Jersey.

It is true, however, that we do not actually digest gum, although it typically passes through the digestive tract in a matter of hours to days. “Very rarely patients can form a bezoar [an indigestible conglomerate trapped in the gastrointestinal tract], which can stay in the digestive system, typically the stomach, for a long time,” adds Boxer. A bezoar can be made of hair, vegetable matter or other substances, including gum. But for this to happen, Boxer notes, someone would typically need to have an underlying disorder and swallow a massive amount of gum.

11. Cranberry juice cures urinary tract infections

What science shows: Chugging cranberry juice won’t help if you have a bladder infection, says Pamela Levin, associate professor of urogynecology at the University of Pennsylvania. “If you have symptoms such as burning while urinating, you typically need antibiotics and care from your doctor,” she says. “[Cranberries] are linked to preventing, not treating, infections.”

12. Avoid exercise if you’re unwell

What science shows: Studies have found that mild to moderate exercise when you have an upper-respiratory infection may help you feel better faster. Lying in bed can weaken your muscles and predispose you to pneumonia, says William Schaffner, an infectious disease expert at the Vanderbilt University School of Medicine. Light exercise prompts you to breathe deeply and cough, which “gets things up.”

13. You must wait an hour after eating before swimming

What science shows: “It is a myth that you need to wait to swim after eating,” says Boxer. The thought here was that when you eat, blood flow is diverted to your digestive system, and this interferes with blood flow to the muscles. “While this is true, it is insignificant to inhibit any necessary blood flow for muscles to swim,” Boxer adds. Some people are a bit more tired while digesting or might have some abdominal cramping, but this is not dangerous enough to affect swimming.

In a review published in 2011, the American Red Cross Scientific Advisory Committee weighed in: “No reported cases of eating before swimming causing or contributing to fatal or non-fatal drowning are reported in any of the literature searched.” They concluded that “currently available information suggests that eating before swimming is not a contributing risk for drowning and can be dismissed as a myth.”

Still, you may want to avoid swimming after eating a huge meal, as you’ll probably feel tired, bloated and unmotivated to swim. Boxer suggests avoiding large, heavy, greasy meals and meals that are hard to digest or have high sugar loads before getting in the pool. 

14. You need 10,000 steps a day to boost your longevity

What science shows: The latest research shows that as few as 6,000 steps a day can do it. One 2022 study found that adults 60 and older who clocked 6,000 to 8,000 steps daily had a 50 to 60 percent lower chance of early death.

15. Running will damage your knees

What science shows: Studies in recent years reveal that running does not raise your risk of knee problems. In fact, pounding the pavement seems to protect your joints. One large study found that runners were half as likely to develop knee osteoarthritis compared with non-runners. Runners typically have stronger quadriceps muscles, which helps to protect the joint, explains Grace Lo, a researcher at Baylor University College of Medicine. 

16. Rest when you have back pain

What science shows: While it’s fine to rest for a day or two after a back flare-up, studies over three decades show that you will recover faster if you remain active, says James Powers, an internal medicine geriatric physician at Vanderbilt University Medical Center. Prolonged bed rest makes most types of back pain worse. “The more you don’t use your muscles, the stiffer you will get,” he says.

17. Joints ache when the weather is about to change

What science shows: Do your joints ache or do you experience muscle stiffness when it gets cold? Although some call this an old wives’ tale, others are quick to deem it legitimate. A survey of 200 participants with knee osteoarthritis found that changes in barometric pressure and ambient temperature made their knee pain worse, while other studies have found no association between rainy days and knee or back pain.

The jury is still out on this one, but experts can’t deny that when it comes to joints aching when the weather cools down, patient experience tends to agree. “We all know that our joints feel worse when there is a low-pressure system coming in, which is why people say they know when the weather is changing,” Luks explains. “Interestingly, research into this topic claims that there is no association between weather and joint pain, but my joints don’t agree with that.”

Linder confirms that this is something he frequently hears as well. “There’s no denying that people when the weather changes say that their joints ache more,” he says. “And that’s been described over and over and over again, so there’s no denying people’s experiences.”

18. If it’s an actual heart attack, you will have chest pain

What science shows: About 42 percent of women and 31 percent of men don’t have chest pain during a heart attack, according to a study published in JAMA. Other symptoms include shortness of breath, light-headedness, nausea and pain or discomfort in the back, neck, jaw, or one or both arms.

19. Air hand dryers are more hygienic than paper towels

What science shows: They may save trees, but air hand dryers in public restrooms don’t remove germs as well as paper towels, according to research. Even worse, they may spread germs around. One study published in the Journal of Hospital Infection found that airborne bacteria counts were 27 times higher when jet air dryers were used.

Editor's note: This article, originally published Jan. 18, 2023, has been updated to reflect new information.

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