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Common Medical Misconceptions
Popular culture is loaded with myths and half-truths. Most are harmless. But when doctors start believing medical myths, perhaps it's time to worry.
In 2007, a study published in the British Medical Journal looked into several common misconceptions, from the belief that a person should drink eight glasses of water per day to the notion that reading in low light ruins your eyesight.
"We got fired up about this because we knew that physicians accepted these beliefs and were passing this information along to their patients," said Aaron Carroll, assistant professor of pediatrics at the Indiana University School of Medicine. "And these beliefs are frequently cited in the popular media."
Click on for the top 7 most common medical myths — debunked.
Myth: Shaved hair grows back faster, coarser and darkerSlide 2 of 15
Myth: Shaved hair grows back faster, coarser and darker
Fact: A 1928 clinical trial compared hair growth in shaved patches to growth in non-shaved patches. The hair which replaced the shaved hair was no darker or thicker, and did not grow in faster. More recent studies have confirmed that one.
Here's the deal: When hair first comes in after being shaved, it grows with a blunt edge on top, Carroll and Vreeman explain. Over time, the blunt edge gets worn so it may seem thicker than it actually is. Hair that's just emerging can be darker too, because it hasn't been bleached by the sun.Slide 3 of 15
Myth: You should drink at least eight glasses of water a daySlide 4 of 15
Myth: You should drink at least eight glasses of water a day
Fact: "There is no medical evidence to suggest that you need that much water," said Dr. Rachel Vreeman, a pediatrics research fellow at the university and co-author of the journal article.
Vreeman thinks this myth can be traced back to a 1945 recommendation from the Nutrition Council that a person consume the equivalent of eight glasses (64 ounces) of fluid a day. Over the years, "fluid" turned to water. But fruits and vegetables, plus coffee and other liquids, count.Slide 5 of 15
Myth: Fingernails and hair grow after deathSlide 6 of 15
Myth: Fingernails and hair grow after death
Fact: Most physicians queried on this one initially thought it was true. Upon further reflection, they realized it's impossible. Here's what happens:
"As the body’s skin is drying out, soft tissue, especially skin, is retracting," Vreeman said. "The nails appear much more prominent as the skin dries out. The same is true, but less obvious, with hair. As the skin is shrinking back, the hair looks more prominent or sticks up a bit."Slide 7 of 15
Myth: We use only 10 percent of our brainsSlide 8 of 15