Fall is drinking season. Between Halloween parties, tailgates, and boozy apple picking trips, Americans will find themselves at the bottom of an increasingly number of bottles. That means bad behavior, sure, but it also means the hiccups, which is weird if you think about it.
The relationship between hiccuping and booze has been thoroughly explored as a trope in real life and fiction: It’s the reflex used to key in an audience that a character has had a few or is lightening up. It bubbles up even in Disney’s uncomfortable 1940s exploration of intoxicated pachyderms.
But the science behind a boozy hiccup is far murkier than its pop culture influences. A hiccup is “a spasmodic, involuntary contraction of the inspiratory muscles, associated with delayed, abrupt glottic closure, causing a peculiar sound,” as defined by physiologist Sandrine Launois and her colleagues at Beth Israel Hospital, Boston, in the journal of the European Respiratory Society in 1993.
That’s what it is, but no one really knows how hiccups became a biological phenomenon. One popular theory posits that these motions are evolutionary holdovers from a time when we, as ancient amphibians, had to suck air across our gills but keep our glottises — the bit at the top of the throat that houses our vocal folds — closed to prevent water from entering the lungs. Or it could be that, since they occur in the womb, they’re preparing babies to breathe. Or it’s to keep the unborn from drowning on amniotic fluids.
For every hypothesis about the origins of hiccups, there are a dozen reasons for how we trigger them. Under causes of chronic hiccups, Launois and colleagues mention alcohol on a list that also includes malingering, neurosyphilis, heroin addiction, and “hair or ant in external auditory canal.” In 1991, Mount Saint Mary’s University biologist Peter Gauthier proposed in the journal BIOS that a hiccup could force a bit of food down the esophagus toward the gut. That alcohol triggers this reflex is simply the nervous system getting confused:
Once the nervous wiring is in place for a reflex, then any stimulus that can bypass the natural one, and active some intermediates in the response, will precipitate that reflex even though there is no apparent reason for it, or any benefit is derived from it. Although the nervous system is good at integrating proper signals with their responses, it can become confused, and in this case direct an unnatural stimulus to activate the neurons that control the hiccup reflex. In this sense drinking an excessive amount of alcohol may be no more related to the hiccup than the Patellar hammer is related to the knee jerk.
The nervous system, as Gauthier lays out, is an appealing target: The vagus nerve controls the diaphragm’s contractions during hiccups, and alcohol certainly can have effects, even long term, on the vagus nerve.
Should you have a case of the booze-induced hics, and sensibly want to get rid of them, grab a lemon from the bar, soak it in bitters, and suck it down — it worked for 14 out of 16 people, anyway, according to a study in the New England Journal of Medicine.