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Cracking your knuckles
will give you arthritis.
Myth! Recent studies haven’t found
a link between cracked joints and
arthritis. But some studies showed
that cracking your knuckles can
result in soft-tissue damage (which
can cause swelling) and a decrease
in handgrip strength.24
You don’t need eight
glasses of water every day.
Truth! There’s no scientific evidence
that eight is the magic number. You
might need more or less than that,
depending on factors such as climate
and body size. To make sure you are
getting enough, just drink water
throughout the day.25
Sitting up straight can be
bad for your back.
Truth! “Hunching can certainly be
bad for your back. But the opposite is
true, too,” says Neel Anand, MD, pro-
fessor of orthopedic surgery and
medical director of spine trauma sur-
gery at Cedars-Sinai Spine Center in
Los Angeles. “Sitting up straight for
too long without a break can also
cause strain.” When you’re sitting,
keep your lower back supported and
your legs uncrossed with your knees
at a 90-degree angle, and get up to
stretch every half hour or so.26
People with dark skin
can’t get skin cancer.
Myth! Dark skin is less likely to burn,but it isn’t immune to harmful
UV rays and the damage they cause.
People of all skin types need to use
sunscreen.27
If you don’t have a
bull’s-eye rash, you
don’t have Lyme disease.
Myth! About 20 to 30 percent of
people with Lyme disease will never
develop that classic rash. Other
symptoms to watch for include fever,
headache, achy muscles, and swol-
len lymph nodes and joints.28
You need less sleep
as you get older.
Myth! Older adults often sleep less
as a result of chronic conditions that
are more common with age as well
as the medications used to treat
them. But that doesn’t mean they
require less sleep. While sleep needs
vary from person to person, the CDC
recommends most adults get at least
seven hours of sleep for optimal
health.29
Holding in a sneeze
is unhealthy.
Truth! As your body gets ready to
sneeze, pressure builds in your lungs.
When your body tries to push the
air out, it needs somewhere to go—
and if you’re pinching your nose and
mouth, it could be rerouted to the
ears. In rare cases, sending the
sneeze in that direction can lead to
damage such as ruptured eardrums.rd.com 73Cover Story Reader’s Digest