ELI5 Spicy Food - What causes my body to react when I eat spicy food?

What causes my body to react when I eat spicy food? Why does my nose run, why do I sweat, what’s going on in my body?   ... We explain like i'm five!   Thank you to the r/explainlikeimfive community, and specifically the following reddit users whose questions and responses formed the basis of this conversation: gametes, 818, rommeltj, magiccorbin, tyler1128, followups, stuthulhu, hothmonster & landowillo95   If you have suggestions, comments, or would like to be a guest on an upcoming episode of this podcast, please reach out to us at [email protected].