This article originally appeared in the San Francisco Chronicle on July 30, 2014.
You might be the type who doesn’t remember the last time you cried, but your body is still producing 5 to 10 ounces of tears every day. And when you reach for the tissues at a wedding or funeral, the tears are different than the ones that emerge when you’re chopping onions.
UC Berkeley researchers compiled these tearful tidbits for an article published in their Wellness newsletter last week. In it, they explained there are three types of tears:
— Continuous (or basal) tears keep the eye lubricated and deliver oxygen and nutrients to parts of the eyes, both in humans and land animals.
— Reflex or irritant tears are those that well up when you’re in the wind or in bright light, when you get something in your eye or when onions release a potent enzyme.
— Psychogenic tears are emotional teardrops and thought to be uniquely human. There have been some anecdotal reports that elephants also shed emotional tears, but research hasn’t confirmed it.
Most of the time, tears drain into tiny openings in the inner corners of your eyes and then into your nasal passage, which is why your nose gets runny when you cry. Tears spill onto your cheeks only when there’s more fluid than the eyes can drain on their own.
A 1980 study revealed women report crying about five times a month compared with men, who reported that they cry just once. But the average length of a crying spell is about six minutes for both.