2. “Cracking your knuckles will give you arthritis”
This would make sense, right? That popping sound hands make when the knuckles are cracked can’t possibly be good for you. However, as How Stuff Works tells us, there’s no direct correlation between the obnoxious habit and the disease. “Cracking accompanied by pain, however, can signify other inflammatory conditions, including tendinitis and bursitis,” they say.
3. “Feed a cold, starve a fever”
“The old adage of ‘feed a cold, starve a fever’ started centuries ago when it was believed that colds were brought about by a drop in body temperature,” Dr. Albert Ahn, MD, tells Health, adding: “The ‘starve a fever’ recommendation likely arose from the belief that eating food activated the gastrointestinal system and raised the body temperature.” As it turns out, you need to consume calories in both scenarios if you want to get better.
4. “Chewing gum takes seven years to digest”
“After having seen hundreds of stomachs, I can say that if you swallow gum, it will not stay in your stomach for seven years as the popular myth describes,” Dr. Sarina Pasricha, MD, MSCR, tells Bustle. For the most part, gum just passes right through your system because your gut enzymes can’t break it down.
5. “You lose the most body heat through your head”
So, there is a little bit of truth to this one, How Stuff Works explains. “In a body at rest, 7 to 10 percent of heat loss occurs through the head. Engaging in work or exercise increases the body’s core temperature and the flow of blood to the brain,” they say. “As the activity continues, however, the blood vessels near the skin in the rest of the body dilate, allowing more blood to flow throughout the body and reducing the flow to the brain.”
6. “You swallow spiders in your sleep”
Good news — this gross old wives’ tale is a work of fiction. While a bug may find its way into your snoring gob on a very rare occasion, this isn’t a normal thing that happens. “Bugs are biologically wired to stay alive, not to walk into peoples’ mouths and be accidentally eaten,” health expert Jaya Jaya Myra tells Bustle.
7. “Your mouth is dirtier than a toilet seat”
Sorry folks, but there’s some truth to this one. While it’s difficult to measure the exact amount of bacteria in the mouth, it’s still estimated to be pretty dirty. Plus, dentist Dr. Ron Baise tells Bustle everyone experiences some form of gum disease throughout their life, which contributes to bad breath and tooth loss. Yuck!
8. “Eating carrots helps improve your eyesight”
This old wives’ tale might still be alive and kicking since it was first conceived during World War II. But to be clear, it’s only partially true. “Carrots are high in vitamin A, a nutrient essential for good vision,” WebMD says. “Eating carrots will provide you with the small amount of vitamin A needed for good vision, but vitamin A isn’t limited to rabbit food; it can also be found in milk, cheese, egg yolk, and liver.”
9. “Caffeine stunts your growth”
No — there’s no direct connection between drinking caffeine and stunted growth. How Stuff Works suggests this myth came about because human growth hormone is secreted during sleep, and since caffeine keeps you awake, there’s a possible correlation. But they reiterate there’s no scientific backing for these claims.
10. “Sitting in a hot tub lowers sperm count”
Studies have found that sitting in a hot tub can, in fact, reduce your sperm count. However, all hope isn’t lost. “Hot tubs will not affect a man’s fertility if the exposure is limited to a few minutes daily or less,” HealthyWomen summarizes via ShareCare.com. “It’s a good idea for a man to avoid prolonged exposure to hot tubs, saunas and steam rooms when a couple is trying to become pregnant. However, occasional visits to the sauna and hot tub will have no effect.”
11. “Kids get hyper from eating too much sugar”
While we’ve been hearing this for years, How Stuff Works says it’s a myth. While simple sugars in candy are rapidly metabolized and can give a burst of energy, they are then quickly carried to other parts of your body for use, no “worked off” in a frenzy. “Sugary snacks and sodas are rightly blamed for their role in obesity and tooth decay. But hyper behavior is one rap you can’t pin on them — unless, of course, they’re caffeinated products like cola or chocolate.”
12. “If you don’t exercise, your muscles will turn into fat”
Long story short: If you don’t exercise, your muscles will shrink, not magically transform into fat. “The confusion arises because if you don’t use your muscles then you lose them because muscle tissue is broken down (as part of the normal cycle of tissue turnover) but then not replaced,” Dr. Susan Jebb tells The Mirror.
13. “Shaving makes hair grow back faster”
“The ‘thicker’ hair is an illusion because removing the tapered tip of the hair leaves it with a blunt end that makes it more visible,” Dr. Rob Hicks tells The Mirror. Shaving also doesn’t make hair grow back faster, he says.
14. “Leaving cuts uncovered makes them heal faster”
Actually, it’s quite the contrary. The Mirror explains that leaving a wound uncovered will cause it to scab and not build new cells as rapidly, where as keeping it covered can help cell production. Plus, “covering a wound also reduces the risk of it becoming infected,” Dr. Hicks says.