Hey BrainStuff, I’m Jonathan and today’s
question is “How do we get hiccups?”
Science isn’t sure, actually.
But it's not that medical science has been
ignoring hiccups.
When these spasms are frequent or persistent
in adults, they can indicate over a hundred
different diseases and disorders, from multiple
sclerosis to cancer to appendicitis.
And hiccups themselves can get serious.
In what’s called intractable cases, hiccups
don’t stop for more than a month and can
go on for years without relief, leading to
complications like irregular heartbeat, weight
loss, insomnia, and emotional distress.
Understandably.
But OK, science isn't totally ignorant here.
We know the basics.
Hiccups are reflexive spasms of the diaphragm
and glottis caused by irritation to any of
several nerves throughout your body.
During normal breathing, you move air into
and out of your lungs partially thanks to
contractions of your diaphragm.
It contracts (pulling downward) as you inhale,
then releases (relaxing upward) as you exhale.
And all that air moves through your larynx
and glottis – that’s the opening between
your vocal cords.
During a hiccup, at least half of the diaphragm
contracts sharply; about 80 percent of the
time, it’s just the left half.
That contraction starts pulling in a deep
breath, but it gets cut short by the glottis
snapping shut about three-hundredths of a
second later.
The “hic” sound comes from that sudden
closure.
In most cases, hiccups are caused by irritation
of the phrenic nerves, which control the motion
of the diaphragm and send your brain sensory
information about what’s going on in various
parts of your neck and body.
That irritation is usually from your stomach
distending when you when you accidentally
swallow air, or when you eat or drink too
much too fast.
Especially carbonated beverages, like soda
and beer.
Irritations of the vagus nerve can also be
hiccup culprits, possibly due to its connection
to the larynx: Anything from ulcers in your
small intestine to a hair poking at the inside
of your ear, and lots of stuff in between.
If you're looking to get rid of hiccups, some
of the most common home remedies really are
worthwhile.
They work by either overloading the phrenic
or vagus nerves or by interrupting your involuntary
breathing cycle.
For nerve overload, try biting into a lemon,
placing a spoonful of sugar on the back of
your tongue, pulling on your tongue, or having
a friend tickle or scare you.
On the respiratory end, try holding your breath,
gulping down a glass of water, or breathing
into a paper bag.
If nothing works, hiccups generally go away
on their own.
If they stick around for more than 48 hours,
see a doctor just in case.
The purpose behind this reflex is still a
mystery.
Some researchers say they could be vestigial
spasms related to how our amphibian ancestors
controlled their gills.
Others postulate that they help with breastfeeding:
Hiccups can release small amounts of air from
the stomach into the esophagus, where it can
be exhaled.
So hiccups might serve to get air out of babies’
stomachs, making more space for milk.
But what do you think?
Do researchers need to look deeper?
Let us know in the comments.
Give us a Like if you learned something, and
for lots more weird science, subscribe -- or
visit our home planet, HowStuffWorks.com.
