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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.
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.
Myth: Fingernails and hair grow after death
Fact: Most physicians who 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."
Myth: We use only 10 percent of our brains
Fact: Physicians and comedians alike, including Jerry
Seinfeld, love to cite this one. It's sometimes
erroneously credited to Albert Einstein. But MRI
scans, PET scans and other imaging studies show no
dormant areas of the brain, and even viewing
individual neurons or cells reveals no inactive areas,
the new paper points out. Metabolic studies of how
brain cells process chemicals show no nonfunctioning
areas.
The myth probably originated with self-improvement
hucksters in the early 1900s who wanted to convince
people that they had yet not reached their full
potential, Carroll figures. It also doesn't jibe with the
fact that our other organs run at full tilt.
Myth: Reading in dim light ruins your eyesight
Fact: The researchers found no evidence that reading
in dim light causes permanent eye damage. It can
cause eye strain and temporarily decreased acuity,
which subsides after rest.
Myth: Eating turkey makes you drowsy
Fact: Even Carroll and Vreeman believed this one until
they researched it. The thing is, a chemical in turkey
called tryptophan is known to cause drowsiness. But
turkey doesn't contain any more of it than does
chicken or beef.
This myth is fueled by the fact that turkey is often
eaten with a colossal holiday meal, often
accompanied by alcohol — both things that will make
you sleepy.
Myth: Cellphones are dangerous in hospitals
Fact: There are no known cases of death related to
this one. Cases of less-serious interference with
hospital devices seem to be largely anecdotal, the
researchers found. In one real study, cellphones were
found to interfere with 4 percent of devices, but only
when the phone was within 3 feet of the device.
A more recent study, this year, found no interference
in 300 tests in 75 treatment rooms. To the contrary,
when doctors use cellphones, the improved
communication means they make fewer mistakes.
"Whenever we talk about this work, doctors at first
express disbelief that these things are not true," said
Vreeman said. "But after we carefully lay out medical
evidence, they are very willing to accept that these
beliefs are actually false."
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.
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.
Myth: Fingernails and hair grow after death
Fact: Most physicians who 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."
Myth: We use only 10 percent of our brains
Fact: Physicians and comedians alike, including Jerry
Seinfeld, love to cite this one. It's sometimes
erroneously credited to Albert Einstein. But MRI
scans, PET scans and other imaging studies show no
dormant areas of the brain, and even viewing
individual neurons or cells reveals no inactive areas,
the new paper points out. Metabolic studies of how
brain cells process chemicals show no nonfunctioning
areas.
The myth probably originated with self-improvement
hucksters in the early 1900s who wanted to convince
people that they had yet not reached their full
potential, Carroll figures. It also doesn't jibe with the
fact that our other organs run at full tilt.
Myth: Reading in dim light ruins your eyesight
Fact: The researchers found no evidence that reading
in dim light causes permanent eye damage. It can
cause eye strain and temporarily decreased acuity,
which subsides after rest.
Myth: Eating turkey makes you drowsy
Fact: Even Carroll and Vreeman believed this one until
they researched it. The thing is, a chemical in turkey
called tryptophan is known to cause drowsiness. But
turkey doesn't contain any more of it than does
chicken or beef.
This myth is fueled by the fact that turkey is often
eaten with a colossal holiday meal, often
accompanied by alcohol — both things that will make
you sleepy.
Myth: Cellphones are dangerous in hospitals
Fact: There are no known cases of death related to
this one. Cases of less-serious interference with
hospital devices seem to be largely anecdotal, the
researchers found. In one real study, cellphones were
found to interfere with 4 percent of devices, but only
when the phone was within 3 feet of the device.
A more recent study, this year, found no interference
in 300 tests in 75 treatment rooms. To the contrary,
when doctors use cellphones, the improved
communication means they make fewer mistakes.
"Whenever we talk about this work, doctors at first
express disbelief that these things are not true," said
Vreeman said. "But after we carefully lay out medical
evidence, they are very willing to accept that these
beliefs are actually false."