Why Do We Get a Runny Nose When We Cry? Uncovering the Secret Passage Behind 'Tears and Snot'

When we cry buckets watching a sad movie, or when chopping onions makes our eyes water profusely, an awkward phenomenon often accompanies it: a runny nose that just won't quit. This comical chain reaction of 'tears and snot' isn't because your brain is confused, but because your face hides a mysterious underground drainage system. Our brains constantly produce tears every day. These tears aren't typically for crying, but rather to lubricate the eyeballs and wash away dust. Under normal circumstances, excess tears quietly flow through small openings on the inner side of the eyes into a duct called the nasolacrimal duct, draining directly into the nasal cavity. They then evaporate with breathing, so we don't notice anything. However, when we get emotionally worked up and cry intensely, the lacrimal glands secrete dozens of times more tears than usual in a short period. These overflowing tears, besides spilling from the eye sockets, all rush like a flood into the nasolacrimal duct, this drainage channel, and pour madly into the nasal cavity. Once a large volume of tears floods the nasal cavity, they mix with the existing mucus, diluting the normally thick snot into a watery consistency. At this point, this liquid mixed with tears flows out of the nostrils due to gravity. So, the 'snot' that runs down your face when you cry is actually more than half your tears!