The Bogus Health Myths Every Gen Xer Grew Up Believing

Gum stays in your stomach for seven years

This was the gastrointestinal ghost story of childhood. Thankfully, your digestive system has better things to do. “Gum, like most foods, is partially digested in the intestines, and the undigested part is eliminated in your bowel movements,” says Dr. Christopher Labos, a cardiologist and an epidemiologist at McGill University in Montreal and author of Does Coffee Cause Cancer?: And 8 More Myths about the Food We Eat. “It will probably be eliminated in one to two days.”

So why did the myth stick? Labos suspects parents and teachers were looking for any available weapon in the endless war against gum chewing, especially the kind that ended under desks. The number helped, too, he says: Seven shows up everywhere, including Snow White’s roommates, the deadly sins and the wonders of the world.

Sitting too close to the TV ruins your eyesight

For kids raised in the glow of a living-room television, “move back” was practically a lullaby. Sit too close, we were told, and your eyes would melt into useless little raisins before the next commercial break.

Not quite. “When we think of permanent irreversible causes of vision loss, common causes are age-related conditions such as glaucoma and age-related macular degeneration,” says Dr. Victoria L. Tseng, an assistant professor in the department of ophthalmology at the UCLA Stein Eye Institute. “Sitting close to a television does not directly cause these conditions.”

What it can do, she says, is irritate the surface of the eye, causing dry eyes. It may also contribute to eye strain, especially in children.

Crossing your eyes makes them stay that way

Make one goofy face too many and your eyes might freeze in place forever, leaving you stuck mid-mischief for the rest of your life.

The human body is not nearly that petty. “Your eyes are controlled by muscles, just like your arms and legs,” Tseng says. Crossing your eyes simply means you’re contracting those muscles on purpose. “Just like your arm will not get stuck over your head if you use an arm muscle to lift it,” she says, “using muscles to cross your eyes will not make the eyes get stuck in a crossed position.”

Shaving makes hair grow back thicker and darker

This was the great teenage grooming threat. Touch a razor to your leg, face or mysterious new patch of adolescent fuzz, and it would return as a dense black forest.

Not true, says Dr. Adam Friedman, a professor of dermatology at the George Washington University School of Medicine & Health Sciences. A razor only cuts the hair shaft at or just above the skin. It never reaches the follicle, where genetics, hormones and the normal hair-growth cycle determine hair thickness, color and growth rate. Shaving is “a surface-level, dead-hair-walking event,” he says. 

That doesn’t mean the myth came from nowhere. Shaving changes the tip of the hair. Uncut hair naturally tapers to a fine point. Shaved hair grows back with a blunt edge, which feels rougher and more noticeable as it emerges.

You lose most of your body heat through your head

Leave the house bareheaded and, according to adult science, your body heat will shoot out of your skull like steam from a manhole.

The idea likely traces back to the 1970s U.S. Army Survival Manual, says John S. Tregoning, a professor of vaccine immunology at Imperial College London and author of Live Forever? A Curious Scientist’s Guide to Wellness, Ageing and Death. The manual warned: “[A]lways keep your head covered. You can lose 40 to 45 percent of body heat from an unprotected head.”

But there was a catch. “The tests were done on people in full snowsuits but no hats,” Tregoning says. In other words, the head was the only exposed body part. If researchers had tested people wearing only hats and nothing else, the rest of their bodies would have looked like a heat-loss disaster zone.

Wearing a hat is still sensible in cold weather, Tregoning says, but not because your head is a thermal chimney.

Urine calms a jellyfish sting

This myth reached peak cultural legitimacy when it became a plot point on Friends. Get stung by a jellyfish, and someone, usually far too confidently, would offer their services.

Please decline. “The first thing to understand is that when a jelly stings you, it doesn’t use all it’s got,” says Christie Wilcox, a science writer and author of Venomous: How Earth’s Deadliest Creatures Mastered Biochemistry. Some stinging cells may still be sitting on your skin, loaded and ready. That means the wrong treatment can make things worse.

“Urine isn’t a good idea because it can actually trigger stinging,” Wilcox says. If bits of tentacle or unfired stinging capsules remain on the skin, urine may cause them to fire, injecting even more venom. Congratulations, you’ve turned a bad situation into a worse one.

For pain, heat is often the better move. “The best thing you can do for yourself is submerge the sting in the hottest water you can stand,” Wilcox says. Heat can interfere with the toxins and relieve pain.

You only use 10 percent of your brain

This was the myth that made every underachiever feel like a secret genius. Sure, you forgot your locker combination, but supposedly 90 percent of your brain was still backstage.

“One problem with this claim is that it’s scientifically unclear, even though it may sound valid,” says Dr. Barry Gordon, a professor of neurology at Johns Hopkins Medicine. Brain activity, he says, is constant. “All the parts of the human brain and nervous system are working or active in some fashion all the time.”

Nicholas Spitzer, a neurobiologist at UC San Diego, puts it simply. “We use all of our brain, although not all at the same time.” If we didn’t, strokes affecting supposedly “unused” regions would not matter. But they do, often devastatingly.

So why does the myth live on? Because it flatters us. Spitzer says it suggests we have hidden brainpower “in reserve,” ready when needed. Sadly, there is no secret 90 percent waiting to turn us into geniuses. Just the same brain, doing its best, wondering where we put the keys.

Feed a cold, starve a fever

This was health advice that sounded old-timey enough to be true, which is always dangerous. If you have a cold, eat. If you have a fever, apparently your body needs to be treated like a misbehaving raccoon and denied snacks.

The saying really is old. Dr. Sharon H. Bergquist, medical director of Emory Executive Health, says the folklore dates back to the 1500s, when people believed a cold meant the body was too cold and needed food to raise its temperature. A fever, meanwhile, meant the body was too hot, so starving it supposedly cooled things down.

“We now know that this old adage is a myth,” Bergquist says. Whether you have a cold or a fever, your body needs energy and hydration to support the immune system in fighting infection. “You need to feed both a cold and a fever,” she says, because the body needs calories to produce immune cells.

So the real rule is less catchy but more useful: Stay hydrated, and eat what you can.