Q: Why do we hiccup?
A: Basically, no one really knows why we hiccup. Scientists know how and by what mechanisms hiccups occur, but why they do is still something of a mystery.
Almost everyone's had hiccups, or singultus"" as it's medically known, at some point in their lives. A single hiccup is the result of an unintentional contraction of your diaphragm, the muscle located just below the lungs.
When it works normally, the diaphragm allows us to breathe air in and out of our lungs, but sometimes it can get irritated and contract suddenly, causing us to suck or gulp down air. This sudden rush of air also causes the vocal cords to close, producing the characteristic ""hic!"" that gives hiccups their name.
But what makes the diaphragm irritated enough to hiccup in the first place? Drinking alcohol is famously thought to do so, since the alcohol can relax the diaphragm and the vocal cords, making it easier for any little disturbance to cause hiccups.
Eating a big meal or drinking a carbonated drink can cause your stomach to expand, which pushes the diaphragm up and makes it more likely to spasm and contract.
Also, eating spicy food, using tobacco, experiencing a sudden change in temperature and even sudden emotional stress or excitement are all thought to irritate the nerves controlling the diaphragm, making malfunctions like hiccups more common.
Just why hiccupping developed, though, remains unknown. Perhaps there's some evolutionary advantage to hiccups we haven't discovered yet, or it could just be an interesting glitch in our hardware.
Christian Straus of the Respiratory Research Group at the University of Calgary, Alberta, Canada, has suggested that hiccups are an evolutionary remnant of amphibian breathing. Frogs, for instance, gulp down air and water in processes quite similar to our mammalian hiccups.
Another theory suggests that hiccups were our primary prenatal breathing mechanism, since inhaling amniotic fluid in the womb might require a different set of motions than breathing air outside of it.
Both the amphibian and amniotic theories may be correct, and each is supported by several facts. However, neither currently has enough evidence to be more than a plausible theory.
Perhaps the most famous aspect of hiccups is the variety of methods suggested to cure them. They range in simplicity from just holding your breath, to getting the daylights scared out of you to bending over and drinking water from a glass while your head's between your knees.
Although the validity of these 'treatments' may be questionable, many swear by their effectiveness. Perhaps the placebo effect and the fact that hiccups usually go away on their own have more to do with it.
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