The Science Behind Hiccups

Jean-Philippe Guillaume | March 1, 2026

Originally Appeared in Issue 5, Volume 1 of the ISS Newsletter.

We’ve all probably experienced the odd, and somewhat slightly annoying occurrence of hiccupping. It is an involuntary reaction your body goes through and seems to come about at the worst possible times. Why do we hiccup? Is there a way to prevent it? And how do you get rid of them?

In all simplicity, hiccups occur when your diaphragm, a large muscle below your lungs that helps you breath, suddenly and quickly contracts. This is immediately followed by the closure of your vocal cords, which make a “hic,” sound.

Looking at it a little deeper, here are the ins and outs of what happens. Hiccups involve a reflex arc, which is the same idea your body uses in response to car hurtling directly at you. Certain stimuli will signal the nerves in your brainstem. These decipher the signal and trigger an immediate reflex. This reflex in response is the diaphragm contracting downwards, and simultaneously having your vocal cords snap shut loudly. This is where the actual “hiccup,” sound comes from.

It all started when nerves detect any form of irritation or sudden input. This is why it can happen if you just drink something carbonated. That triggers this involuntary reflex.

So how can you prevent hiccups if they really irritate you and you get them often? You can start by eating slower and chewing your food more thoroughly. Don’t gulp a lot of air while chewing or drinking. Then, if they’re “caused by stress,” learn to manage your stress better. Further research says to avoid excessive amounts of carbonated drinks and alcohol.

Finally, how can you stop them? One way is by holding your breath. This increases the carbon dioxide in your bloodstream, which relaxes the diaphragm. Another way is to drink water. Anything that interrupts the hiccup reflex or increases your carbon dioxide can help.