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What's the Science Behind Why We Hiccup?

Lots of things seem to trigger the involuntary reflex known as the hiccups, but does science understand why that reflex happens in the first place?

By
Sabrina Stierwalt, PhD,
Episode #350
hiccup

Sometimes they're funny. Sometimes they're annoying or even frustrating. They can disrupt you at the most inconvenient times. No, I'm not talking about your family members—good guess, though! I'm talking about hiccups.

What are hiccups? And are there scientific reasons behind why we get them?

The world's longest bout of hiccups

According to the Guinness World Records book, the record for the longest bout of hiccups goes to Charles Osborne. He had the hiccups for 68 years, from 1922 to 1990, with an estimated 430 million hiccups. Christopher Sands experienced something like 10 million hiccups over 27 months from 2007 to 2009. He hiccupped every two seconds for 12 hours a day.

Charles Osborne had the hiccups for 68 years, from 1922 to 1990, with an estimated 430 million hiccups.

Folklore tells us that getting the hiccups means someone is talking about you or missing you. If you go through a list of your friends in your head, your hiccups will stop when you get to the memory of the friend who is the culprit. In medieval times, hiccups were thought to be caused by elves.

The mechanics of hiccups

Your diaphragm, the large muscle that sits just below your lungs and above your stomach, helps you breathe. It moves upward to force air out of your lungs and downward to pull air in. Even though we don’t have to think about it each time—although we can direct it if we want to: breathe in, breathe out—our brain signals our diaphragm to make these movements.

Sometimes our brain signals our diaphragm to move downward more forcefully than normal.

Sometimes our brain signals our diaphragm to move downward more forcefully than normal. This sharp, involuntary muscle contraction causes air to get sucked into the back of your throat. The area of your throat near your vocal cords then snaps closed, thanks to this change in pressure, creating a “hic” sound.

Why do we hiccup?

We understand the mechanics of hiccups—they're an involuntary reflex. But why does our brain send a signal to create that reflex in the first place? Scientists have tried to pin down a clear reason, but so far, we still don’t know.

Although we don't know exactly why our brains signal us to hiccup, we do know that many things trigger the reflex. Research has seen hiccups triggered by trauma (like head injuries), tumors or goiters, infections (including meningitis and encephalitis), abdominal distension, and issues with the central nervous system like multiple sclerosis. Irritations like heartburn, spicy food, gastritis, reflux, and ulcers have also been linked to hiccups. One person’s hiccups were even caused by a hair brushing against their tympanic membrane, the membrane that vibrates in response to sound waves and enables us to hear. 

Persistent hiccups can be a sign of a health problem.

We also know of a few behaviors that can lead to hiccups: smoking cigarettes, putting ourselves through a sudden change in temperature, experiencing some sort of heightened emotion like excitement or stress, or overfilling our stomachs (with food, alcohol or even air). 

Nonstop hiccupping can be seriously inconvenient, especially if it affects your ability to eat, sleep, or communicate. Persistent hiccups can be a sign of a health problem, whether it be an ear infection, kidney failure, laryngitis, or a hernia. In the case of Christopher Sands and his 10 million hiccups, he was found to have a brain tumor that pushed on the phrenic nerve—that’s the nerve tasked with signaling the hiccup reflex. Once he had surgery to remove the tumor, his hiccups stopped. 

Are hiccups linked to evolution?

Our bodies rarely develop reflexes for no reason, so some scientists have come up with broader ideas for why hiccupping could be linked to our evolution. For example, because we're mammals, we suckle as babies. The act of nursing can put extra air in our stomachs. Hiccups may be a mechanism we have developed to get rid of that extra air.

Parents know that young babies tend to get the hiccups more frequently than adults. This might be because hiccups play some sort of beneficial role in early development. Or it could simply mean that their stomachs are small and thus more easily filled. 

How do you get rid of the hiccups?

There are lots of folk remedies for brief bouts of hiccups. Some say you can get rid of the hiccups by rubbing the back of your neck, holding your breath, breathing into a paper bag, gargling, drinking ice water, or biting into a lemon. These remedies are supported more by anecdotal evidence rather than scientific studies.

Some people even turn to acupuncture and hypnosis for more persistent hiccup issues. You can also try avoiding possible triggers like large meals, spicy food, and carbonated beverages. 

You can try avoiding possible triggers like large meals, spicy food, and carbonated beverages.

As a kid, I was always told to bend at the waist and try to drink water from a cup while my head was hanging upside down. In hindsight, this sounds like a terrible idea. If it was ever effective, it was most likely the distraction of performing such an impossible task that made the hiccups go away.

My daughter and I try to startle each other if one of us gets the hiccups, although we do that more because it’s fun to yell “boo!” than because we think it actually helps. The best cure for the hiccups seems to be to wait a few minutes until they subside.

ABOUT THE AUTHOR

Dr. Sabrina Stierwalt is an extragalactic astrophysicist at the California Institute of Technology and Adjunct Faculty at the University of Virginia. Stay in the science loop! Listen and subscribe to the Everyday Einstein show on Apple, Spotify, or wherever you get your podcasts.

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About the Author

Sabrina Stierwalt, PhD

Dr. Sabrina Stierwalt is an extragalactic astrophysicist at the California Institute of Technology and Adjunct Faculty at the University of Virginia.

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