What if you never got hiccups?

Hic! Hic! Sometimes hiccups just pop out.

You didn't ask for them. They come all by themselves! What if you never got hiccups at all?

You're sitting quietly when suddenly: hic! Then again, and again. Hiccups seem to arrive out of nowhere, and they usually leave just as mysteriously.

So what if your body never made hiccups at all? Would you miss anything? To answer that, we need to know what a hiccup is, which muscle makes it, and whether hiccups might do any useful job. Scientists have some surprising clues, and a few open questions.

Hiccups are a reflex: the body produces them without any decision on our part. MedlinePlus describes a hiccup as an unintentional spasm of the diaphragm followed by quick closure of the vocal cords.

This thought experiment removes the reflex entirely. To judge what would change, it follows three threads: the mechanics of a hiccup, the role of the diaphragm in breathing, and the evidence about whether hiccups serve a purpose, separating established facts from reasoned ideas.

Most hiccups only last a few minutes. Then they stop by themselves.

Babies hiccup a lot. Babies even hiccup before they are born!

Hiccups are very common, and most of the time they stop on their own after a few minutes. The NHS, the UK's health service, says people often notice them after eating or drinking, or when feeling stressed or excited.

Babies are hiccup experts. MedlinePlus says hiccups are common and normal in newborns and infants. Researchers at University College London report that hiccups begin before birth, about 9 weeks into a baby's growth in the womb, and that babies born early spend about 1% of their time hiccuping: roughly 15 minutes a day.

MedlinePlus notes that hiccups often start for no apparent reason and most often disappear after a few minutes; they are common and normal in newborns and infants. The NHS lists stress, strong emotions such as excitement, and eating and drinking as triggers some people notice.

A 2019 UCL news release on a study in Clinical Neurophysiology reported that hiccups begin in the womb at about nine weeks' gestational age, among the earliest established patterns of activity, and that pre-term infants spend an estimated 1% of their time hiccuping, roughly 15 minutes a day.

Now pretend hiccups are switched off. No more hic!

You would still breathe just the same. But tiny babies might miss something.

If hiccups were switched off, your breathing would carry on just as before: the diaphragm would keep working steadily, breath after breath. For most older children and adults, no more hiccups might just mean no more annoying interruptions.

But babies might be different. Researchers have found that every hiccup in a newborn sends a big wave of signals through the baby's brain. They think this might help the brain learn about the breathing muscles. Without hiccups, babies might need another way to learn. That last part is an idea, not a proven fact.

Removing the reflex would probably leave ordinary breathing untouched: OpenStax describes respiratory groups in the medulla oblongata that keep the breathing rhythm by stimulating the diaphragm and intercostal muscles. For older children and adults, whose hiccups appear to be mainly a nuisance, the loss might go unnoticed.

The interesting case is early life. The UCL team recorded the brain activity of 13 newborns and found each hiccup evoked a pronounced response in the cortex. They suggest it may help the brain learn to monitor the breathing muscles. If so, a hiccup-free infant might need other routes for that learning; how much it would matter is unknown.

Under your lungs is a big muscle called the diaphragm. It helps you breathe in.

Sometimes it gives a sudden jump. Air rushes in, and a flap in your throat snaps shut. Hic!

Your diaphragm is a dome-shaped muscle under your lungs. When it tightens and moves down, it makes room in your chest, and air flows into your lungs. When it relaxes, the air flows back out.

A hiccup happens when the diaphragm gives a sudden, unplanned twitch. Air starts rushing in, but then your vocal cords, the parts of your throat that make your voice, snap shut very quickly. That quick closing is what makes the 'hic' sound.

OpenStax describes normal inspiration: the diaphragm contracts and moves inferiorly, enlarging the thoracic cavity, so pressure in the lungs falls and air flows in; quiet expiration is passive, as the lungs recoil when the diaphragm and intercostal muscles relax. Adolescents and adults typically breathe 12 to 18 times a minute.

In a hiccup, the diaphragm contracts involuntarily, and the vocal cords close quickly afterward, producing the characteristic sound (MedlinePlus). Why the reflex exists is not entirely clear, as UCL's lead author, Kimberley Whitehead, put it, though its frequency in fetuses and newborns hints at a developmental role.

People try lots of tricks to stop hiccups, like sipping cold water.

Tricks don't always work. But most hiccups stop all by themselves.

People have many favorite tricks for stopping hiccups. The NHS lists some that people find helpful, such as sipping ice-cold water or holding your breath for a short time. But it also says there's no evidence that these work for everyone.

The good news is that most hiccups go away on their own after a few minutes. The NHS says you can usually just wait for them to stop, and it lists things some people avoid, such as fizzy drinks and eating very quickly.

Many remedies are passed around. The NHS lists several that people find helpful, including sipping ice-cold water and holding the breath briefly, while stating there is no evidence they work for everyone. MedlinePlus lists similar home measures.

Because most episodes resolve within minutes regardless, it is hard to tell whether a remedy worked or the hiccups simply ended; that is one reason anecdotes are weak evidence. The NHS also says hiccups should only last a few minutes and that people can usually wait for them to go away.