Hiccups often occur after eating a lot, swallowing large amounts of air or drinking a lot of carbonated beverages. In old cartoons, hiccups often accompany someone who drank to much alcohol. But why do we get them?
What happens when you hiccup?
First, let’s explain what happens inside your body when a hiccup occurs. When you hiccup, your diaphragm (the muscle responsible for moving the lungs so you can take in and expel air) and nearby muscles convulse. This causes you to briefly gulp some air. Within 30 milliseconds, the glottis (vocal folds your throat) slams shut, producing the characteristic “hic” sound.
Hiccups can be a very short occurrence. If they stop before the seventh or so, you’re in luck because that’s the end of them. If they last longer than seven, then the odds are good that you are in it for the duration. On average, you typically will hiccup 65 times or more. The hiccup record is currently at 68 years according to Guinness World Records.
Aside from beer, soda, and eating too much, there are some pretty serious conditions which can also cause hiccups. Like tuberculosis, skull fractures, myocardial infarction, epilepsy, meningitis, diabetes mellitus, bowel obstruction, and ulcerative colitis.
So “why” do we hiccup?
There is no definitive answer, but scientists are pretty sure they have an idea. Unlike gagging, puking, sneezing, etc, hiccups serve no currently known function. Until recently, scientists believed that hiccups represented a vestigial remnant of a primitive reflex whose functional or behavioral significance that was lost (like the appendix). New research now proposes that the hiccup is an evolutionary remnant of earlier amphibian respiration.
Many amphibians (like frogs) gulp air and water via a rather simple motor reflex akin to mammalian hiccuping. To support this claim, they observe that the motor pathways that enable hiccuping form during early fetal development, before the motor pathways that enable normal lung ventilation form. Which means that the hiccup is likely an evolutionarily precursor to modern lung respiration. This also explains why premature infants spend 2.5% of their time hiccuping — they are gulping just like amphibians, because their lungs are not yet fully formed. These hiccups are part of fetal development and are associated with the myelination of the Phrenic nerve.
The phrenic and vagus nerve goes all over the body, which is why so many things can cause hiccups if stimulated. For example, a 16 year old girl began hiccuping after a blow to the jaw. The brain scan revealed that one of her blood vessels was pressing against the vagus nerve in her neck.
So how do we cure hiccups?
Most home remedies rely on disrupting the cycle of hiccups. Some include holding your breath, breathing into a paper bag, drinking water while covering your ears or upside down, pulling your tongue, pressing on the eyeballs, sudden fright etc.. These are mostly old wives tales, but can occasionally work. For instance, simply drinking water to wash down a hunk of food that might have been pressing on a nerve can cure hiccups.
There are some drugs that can treat hiccups, but that largely relies on knowing what is causing them in the first place. For most people however, hiccups will eventually subside on their own.