What actually happens when you hiccup?
Every 'hic' is your diaphragm jerking and your vocal cords slamming shut 35 milliseconds later, a reflex that may date back to suckling babies, or even to tadpoles.
▶ Start the storyA hiccup is a reflex in two quick moves. First, your diaphragm, the sheet of muscle under your lungs that powers your breathing, gives a sudden involuntary jerk, pulling in a gulp of air. Then, about 35 milliseconds later, the gap between your vocal cords snaps shut and stops the air in its tracks. That abrupt stop is the 'hic'. The reflex can repeat several times a minute, often with an oddly steady rhythm.
Why would a body do something so pointless? One leading idea is that it isn't pointless for babies. Suckling mammals inevitably swallow air along with milk, and a hiccup creates suction in the chest that pulls air up out of the stomach so it can be burped out, leaving more room for milk. That would explain why babies hiccup so much, why hiccups fade with age, and why they have only been described in mammals. Another idea goes back even further: the hiccup may be a leftover of the gulping reflex tadpoles use to push water across their gills.
Most bouts are over within half an hour. Folk cures abound, but no treatment is known to work especially well. Spare a thought for Charles Osborne, an American farmer who started hiccuping in 1922 after a hog fell on him, and didn't stop for 68 years.
68 years
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Recap
Diaphragm jerks, vocal cords slam shut: 'hic'. Most bouts pass on their own within half an hour.
Surprising fact · Premature babies spend about 2.5% of their time hiccuping.
Sources (3)
No source, no claim. Every fact in this lesson (16 claims) cites at least one of these.