Hiccups

How it works

The diaphragm is the sheet of muscle under the lungs. It pulls down to draw air in³. A hiccup starts when the diaphragm contracts suddenly and without warning. Air rushes into the throat. A split second later the glottis, the opening between the vocal cords, snaps shut. The rush of air stops dead against the closed cords. That makes the “hic”¹.

The reflex runs through the phrenic and vagus nerves and a control centre in the brainstem⁵. Common triggers are eating too fast, a full stomach, fizzy drinks, alcohol, sudden excitement, and a quick change in temperature⁵⁶. Babies hiccup in the womb, and newborns hiccup often¹.

A normal bout lasts a few minutes and stops on its own. Hiccups that last more than 48 hours are called persistent¹. Bouts that go on for more than a month are called intractable¹. These are rare, and they can be serious¹.

No one knows what hiccups are for. One hypothesis, put forward by Straus and colleagues in 2003, is that the reflex is a leftover from our distant ancestors¹. Tadpoles and some amphibians breathe by gulping water through the mouth and pushing it out over the gills while closing the glottis. The muscle pattern of a hiccup is very similar. This is an idea, not an established fact.

How common it is

Ordinary hiccups are universal and nobody has needed to count them, since almost everyone gets them starting before birth¹. The rarer, medically significant forms are better documented. Persistent hiccups, lasting more than 48 hours, and intractable hiccups, lasting more than a month, are rare¹. Those long bouts are more common in men¹.

Is it a problem?

Usually not. A short bout of hiccups is harmless and usually stops on its own¹. It is only rarely a sign of a heart problem¹.

See a doctor if hiccups:

• last more than 48 hours,
• keep coming back and affect your daily life⁶.

Long-lasting hiccups are sometimes linked to problems in the nerves, chest, or digestive system, and a doctor can check for those causes¹.

History and culture

Charles Osborne of Iowa began to hiccup in 1922 and did not stop until 1990, a run of 68 years². He hiccuped about 20 to 40 times a minute⁴. He held down a job, married twice, and had eight children⁴.

Dozens of folk cures exist: holding your breath, drinking from the far side of a glass, a spoon of sugar, a sudden fright. None has strong evidence. Most of them do change breathing and pressure in the chest, which may reset the reflex¹.