Hiccups happen when a person’s intake of air becomes momentarily blocked. It can happen for no apparent reason. It is usually a minor nuisance, but prolonged hiccups can indicate a serious medical problem.

When a hiccup forms, it is because of a sudden, involuntary contraction of the diaphragm at the same time as a contraction of the voice box, or larynx, and a total closure of the glottis. This results in a sudden rush of air into the lungs, and the familiar “hic” sound.

The glottis is the middle part of the larynx, where the vocal cords are located.

Hiccups are medically known as synchronous diaphragmatic flutter or singultus (SDF). They can occur individually or in bouts. They are often rhythmic, meaning that the interval between each hiccup is relatively constant.

Most people have hiccups from time to time, and they usually resolve without treatment within a few minutes.

Rarely, there may be prolonged or chronic hiccups, which can last a month or more. Hiccups that last over 2 months are known as intractable hiccups.

If a bout lasts longer than 48 hours, this is considered persistent, and the person should see a doctor. It could be a sign of a more serious medical condition. This tends to be more common in men than in women.

The longest recorded case of hiccups lasted 60 years.