Hic!

There it is.

That tiny, involuntary noise that can appear out of nowhere, interrupt a conversation, ruin a quiet evening and, in particularly stubborn cases, make you question whether your body has decided to rebel against you.

But why do we get hiccups in the first place?

The surprisingly complicated answer involves your diaphragm, nerves, your brainstem and a reflex that scientists still don’t completely understand.

So let’s take a look at the strange science behind one of the human body’s most ridiculous features.

What exactly is a hiccup?

A hiccup is an involuntary reflex.

It happens when your diaphragm suddenly contracts. The diaphragm is the large muscle underneath your lungs that plays a major role in breathing.

Normally, when you breathe in, your diaphragm contracts and moves downward, helping air enter your lungs. When it relaxes, air is pushed back out.

A hiccup is different.

Instead of following the normal breathing rhythm, the diaphragm suddenly spasms.

Almost immediately afterwards, your vocal cords snap shut.

That sudden closure produces the familiar:

“Hic!”

So, technically speaking, your hiccup isn’t just your diaphragm having a tantrum. It’s a rapid sequence involving muscles, nerves and your vocal cords.

Why does the diaphragm suddenly spasm?

This is where things get interesting.

Scientists know quite a lot about how a hiccup happens, but the exact reason the human body has this reflex in the first place is still not completely understood.

A typical hiccup reflex involves signals travelling through several parts of the nervous system, including the phrenic nerve, which controls the diaphragm, and the vagus nerve, which carries information between the brain and various organs.

The brainstem is also involved.

Essentially, something triggers the reflex pathway, the diaphragm contracts suddenly, your vocal cords close and…

Hic!

Your body has just performed a tiny involuntary reboot.

What causes hiccups?

Fortunately, most hiccups aren’t caused by anything serious.

They can be triggered by surprisingly ordinary things, including:

• Eating too quickly
• Eating a large meal
• Drinking fizzy drinks
• Drinking alcohol
• Swallowing air
• Sudden changes in temperature
• Laughing
• Excitement
• Stress
• Sudden emotional reactions

You may have noticed that hiccups sometimes appear after eating a large meal.

That’s not particularly surprising. A very full stomach can potentially irritate or stimulate structures involved in the hiccup reflex.

Fizzy drinks can also be a culprit because you’re effectively introducing a lot of gas into your digestive system.

And then there is alcohol.

Alcohol has an impressive ability to turn otherwise ordinary bodily functions into bizarre little experiments.

Hiccups are no exception.

Why do babies get hiccups so much?

Babies are famously good at hiccuping.

You may even notice a baby hiccuping before birth.

Fetal hiccups can occur during pregnancy, although researchers aren’t entirely sure what purpose they serve.

One interesting theory is that the reflex may have an evolutionary connection to early breathing development.

Babies also have relatively immature nervous and respiratory systems, so their breathing-related reflexes can behave somewhat differently from those of adults.

In other words, babies aren’t necessarily doing anything wrong.

Their bodies are simply still figuring out the controls.

Is there an evolutionary reason for hiccups?

Here’s one of the biggest mysteries.

Why do humans hiccup at all?

Researchers have proposed several theories.

One possibility is that the hiccup reflex is an evolutionary leftover from our distant ancestors.

Some scientists have suggested that hiccups could be related to ancient breathing mechanisms found in amphibians and other animals.

Another theory is that the reflex may have played a role in helping young mammals coordinate sucking, swallowing and breathing.

But there is no universally accepted explanation for why humans retain the hiccup reflex.

This is one of those areas where science has a surprisingly honest answer:

We know what happens. We’re still working out why.

And that’s actually one of the most interesting things about science.

Why do hiccups sometimes happen when we laugh?

You’ve probably experienced this one.

You’re laughing so hard that suddenly…

Hic!

Laughter can alter your normal breathing pattern. You may take in air rapidly, swallow more air than usual or experience changes in pressure around your chest and abdomen.

Those changes may help trigger the hiccup reflex in some people.

It’s also possible for strong emotional reactions such as excitement, nervousness or stress to contribute.

So if you’ve ever started hiccuping during an important conversation, your body may simply have decided that the situation wasn’t awkward enough already.

How long do hiccups normally last?

For most people, hiccups disappear within a few minutes.

Occasionally, however, they can last much longer.

Doctors generally divide prolonged hiccups into categories based on their duration.

Short-term hiccups

These are the ordinary hiccups almost everyone experiences.

They usually disappear on their own relatively quickly.

Persistent hiccups

Hiccups lasting for more than 48 hours are considered persistent.

That’s unusual and can sometimes be associated with an underlying medical condition or medication.

Intractable hiccups

Hiccups lasting for more than a month are extremely rare and are known as intractable hiccups.

At that point, they’re no longer just an annoying dinner-table problem and should be medically evaluated.

If hiccups persist for more than 48 hours, repeatedly interfere with eating or sleeping, or are accompanied by other concerning symptoms, it’s sensible to speak to a healthcare professional.

Why do people hold their breath to get rid of hiccups?

This is where the internet gets involved.

There are countless supposed cures for hiccups:

• Holding your breath
• Drinking water
• Drinking water upside down
• Swallowing sugar
• Pulling your knees towards your chest
• Being frightened
• Having someone surprise you
• Breathing into a paper bag

Some of these may appear to work.

But here’s the catch:

Hiccups often disappear by themselves.

If you try a bizarre hiccup cure and your hiccups disappear 30 seconds later, it can be difficult to know whether the trick actually worked or whether the hiccups were simply about to stop anyway.

Holding your breath may potentially influence the reflex by changing carbon dioxide levels and breathing patterns, but there isn’t a magical off switch hidden inside your lungs.

And despite what your uncle may tell you, being suddenly frightened is not a scientifically guaranteed treatment.

Why does drinking water sometimes help?

Slowly drinking water can alter your breathing and swallowing patterns.

The swallowing process involves many of the same nerves and muscles that are located around the upper digestive and respiratory systems, so changing that activity may sometimes interrupt the hiccup reflex.

But again, there isn’t a guaranteed cure.

Sometimes the hiccups simply stop.

Sometimes they don’t.

Sometimes you drink half a litre of water and discover that you now have two problems.

Can you actually stop hiccups instantly?

Unfortunately, there is no universally reliable home method that switches hiccups off instantly.

Most ordinary bouts of hiccups resolve without treatment.

If you get occasional hiccups, the sensible approach is generally to remain calm, breathe normally and give them some time.

Trying increasingly ridiculous internet remedies is optional.

Can hiccups be dangerous?

Ordinary hiccups are almost always harmless.

The problem is when they become prolonged.

Long-lasting hiccups can interfere with:

• Eating
• Drinking
• Sleeping
• Talking
• Breathing comfortably
• General quality of life

Persistent hiccups can occasionally be associated with conditions affecting the nervous system, digestive system or other parts of the body.

That doesn’t mean that a two-minute bout of hiccups is a medical emergency.

It means that hiccups that refuse to leave should not simply be ignored indefinitely.

What is the longest case of hiccups ever recorded?

One of the most famous cases involved an American man named Charles Osborne.

According to Guinness World Records, Osborne began hiccuping in 1922 and continued for decades.

His hiccups reportedly lasted approximately 68 years.

Yes.

Sixty-eight years.

That means he spent longer hiccuping than many people spend working, raising children and complaining about their neighbours combined.

Eventually, the hiccups stopped.

Osborne died in 1991 at the age of 97.

His extraordinary case remains one of the strangest examples of prolonged hiccups ever documented.

So, why do we get hiccups?

The short answer is:

Because your body has a reflex involving your diaphragm, nervous system and vocal cords that occasionally activates when it doesn’t need to.

The longer answer is considerably more interesting.

Hiccups are produced when the diaphragm contracts suddenly, followed by rapid closure of the vocal cords. Everyday things such as eating quickly, drinking fizzy drinks, alcohol, laughing and sudden emotional changes can trigger the reflex.

What scientists still don’t completely know is why humans have the reflex in the first place.

And that makes hiccups a great example of something that happens constantly in our bodies while remaining surprisingly mysterious.

So the next time someone asks why you’re hiccuping, you can give them the scientific explanation.

Or you could simply say:

“My diaphragm has decided to become a percussion instrument.”

Both answers are technically acceptable.

Frequently Asked Questions

Why do I get hiccups after eating?

Eating quickly, eating a large meal or swallowing extra air can potentially stimulate the reflex pathways involved in hiccups. Fizzy drinks and alcohol can also make hiccups more likely.

Why do hiccups happen when you drink alcohol?

Alcohol can irritate the digestive system and influence the nervous system. Drinking alcohol may also encourage faster eating, swallowing air and consuming larger meals, all of which can contribute to hiccups.

How do you get rid of hiccups?

Most hiccups disappear naturally. Drinking water slowly, temporarily altering your breathing pattern or holding your breath may help some people, but there is no guaranteed instant cure.

Are hiccups dangerous?

Ordinary hiccups are generally harmless. However, hiccups lasting more than 48 hours are unusual and should be discussed with a healthcare professional, particularly if they interfere with eating, sleeping or breathing.

Why do babies get hiccups?

Babies commonly experience hiccups because their developing nervous and respiratory systems are still maturing. Hiccups can also occur before birth.

Why are hiccups called hiccups?

The word describes the characteristic sound produced when the vocal cords suddenly close after the diaphragm contracts. Different languages have developed their own versions of the sound, but thankfully humans everywhere seem to agree that it is annoying.

The Bottom Line

Hiccups are one of those wonderfully strange reminders that the human body isn’t quite as perfectly engineered as we sometimes imagine.

Your diaphragm suddenly contracts.

Your vocal cords slam shut.

Your brain watches the whole thing happen.

And then you make a noise that sounds like a malfunctioning cartoon character.

Most of the time, there’s nothing to worry about.

But behind that silly little “hic!” is a surprisingly complicated reflex involving your breathing muscles, nervous system and brain.

And scientists are still figuring out exactly why evolution decided we needed it.

Science is weird. Your body is weirder.

This article is intended for general information and education and isn’t a substitute for medical advice.

If you enjoyed this strange fact, dive deeper into the science behind some of the body’s most unusual behaviours here.