Biology
How do hiccups help our body maintain balance?
Quick fact
Hiccups are caused by involuntary spasms of the diaphragm, followed by sudden closure of the vocal cords, producing the characteristic 'hic' sound.
Why this is interesting
Hiccups are a reflex that serves no obvious purpose in adults—but they're nearly identical to the breathing mechanism of tadpoles, suggesting they're a ghost of our aquatic evolutionary past.
Read the full explanation
Understanding How do hiccups help our body maintain balance?
The diaphragm contracts abruptly, pulling air into the lungs, but the glottis (vocal cord opening) snaps shut milliseconds later, creating the sound and interrupting the breath.
A deeper explanation
Scientists believe hiccups are a vestigial reflex from ancient air-breathing fish and amphibians that needed to gulp air while keeping water out of their lungs. The brainstem pattern that triggers hiccups is almost identical to the neural circuit that controls breathing in amphibians. Hiccups are also common in fetuses, suggesting they may help develop the breathing muscles before birth. While they serve no adult function, treatments range from holding your breath to drinking upside-down—all of which reset the vagus nerve and stop the spasm. So every hiccup is a million-year-old reflex that your body just can't let go of.