Tip:
Highlight text to annotate it
X
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.