• Question: What causes us to hiccup?

    Asked by bealeewh to Stu, Martin, Mark, Jenni, Helen on 18 Jun 2011. This question was also asked by yatestwh, cfib.
    • Photo: Mark Burnley

      Mark Burnley answered on 18 Jun 2011:

      Hiccups are very annoying, but also very interesting (physiologically). Hiccups are caused by spontaneous contractions of the diaphagm (the muscle that you use to breathe in) which is in turn caused by the phrenic nerve firing repeatedly without you wanting to breathe in. This is one reason why there are so many “hiccup cures” that involve altering your breathing (by drinking water, scaring somebody to make them gasp or by holding your breath for 30 seconds). None of these really work, and we think that hiccups themselves might be an evolutionary “hangover” from when our ancestors had gills and needed to work muscles to move water across those gills.

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