What causes the hiccups?
Hiccups happen because of spasmodic contractions of your diaphragm.
When your diaphragm contracts, your lungs inhale sharply. This intake of breath in the throat causes that little “hic” sound.
People hiccup from childhood though old age. Pregnant women sometimes feel their babies hiccuping inside the womb. You might get hiccups if you laugh too hard, or eat spicy food, or if your stomach becomes bloated.
What’s happening is an irritation of either the vagus or the phrenic nerve. Those are the nerves that control your diaphragm and your voice box. That irritation causes your diaphragm to contract repeatedly and irregularly.
Everyone has a favorite hiccup remedy. You can drink water upside down, or get someone to scare you. Increasing the amount of carbon dioxide in your body can reduce the hiccups’ frequency. That’s why holding your breath might work. Or stimulating the area of your throat above the esophagus might help, by drinking a glass of ice water.