Still Trying to
Explain ...
- The hanging ball at the back of
your throat. Scientists don’t under-
stand exactly what the uvula does,
but because it is largely unique to
humans, they suspect it plays a role
in speech, possibly secreting enough
saliva to lubricate the mouth while
speaking and swallowing. You may not
need a uvula to speak English. But for
speakers of languages such as French
and Arabic that use sounds known as
uvular consonants (the r in the French
word maître, for example), a missing
uvula may alter their speech. - Hypnic jerks. An estimated
70 percent of people have felt a sud-
den jerk right before they fall into
a deep sleep. Research hasn’t pin-
pointed the reason behind these so-
called hypnic jerks, but one theory is
that as your breathing and heart rate
slow down, your muscles start to re-
lax and may twitch. It could also be
that the brain sends a signal to your
muscles to tense up because it mis-
interprets their relaxation as a sign
that you’re falling. - “Old-people smell.” A small study
from 2012 confirmed that older people
have a less intense scent (some call
it musty or grassy) than young and
middle-aged folk. It’s not clear what
causes this shift in odor as we get
older, but researchers speculate that it
might be due to a type of white blood
cell supply that increases as we age.- Different blood types. Scientists
aren’t sure why humans have differ-
ent blood types. There does appear
to be an association between blood
types and certain diseases. For exam-
ple, people with blood type A are at
a higher risk for some forms of stom-
ach and pancreatic cancer compared
with people with blood type O, who
are more likely to have ulcers and rup-
tured Achilles tendons. - Random eyelid twitching. A
twitchy eyelid can last anywhere from
minutes to days. Most of these
twitches are harmless and don’t affect
your vision. “We don’t know why this
happens exactly, but fatigue, caffeine,
and stress are common culprits,” says
Dr. Rantala. Try applying a warm
compress to your twitchy eye and gen-
tly massaging the lid with your fingers
to relax the muscles.
34.Yawning. While there’s no short-
age of theories, the true reasons for
yawning remain a mystery. One the-
ory suggests that the deep inhalation
and short exhalation of a yawn in-
crease blood flow to the brain, cooling
it down. Another explanation is that
a yawn gives your body a jolt, since
your heart rate increases and your eye
muscles tense up after you yawn.rd.com | june 2019 63Cover Story Reader’s Digest