13 Facts You Never Knew about Human Tears

These facts about tears are pretty eye-opening.

Humans make three different versions of tears

Basal tears lubricate our eyes, reflex tears form in response to irritants such as smoke and dirt, and emotional tears flow when we’re sad or overjoyed. All are made of salt water mixed with oils, antibodies, and enzymes, but they each also contain different molecules. Emotional tears, for example, carry protein-­based hormones, including leucine-enkephalin, a natural painkiller released when the body is under stress.

Onion tears are obviously of the reflex variety—but what’s the irritant?

It turns out onions secrete a compound to deter predators—aka some hungry human wielding a blade—called lacrimatory f­actor. To cut down on its release, refrigerate the onion before slicing, then use a sharp knife to reduce the damage to the onion and the release of the compound.

The Latin word for a tear, lacrima, is at the root of scientific tear-minology

Tears are generated in the lacrimal gland, which sits above the eye just under the ­eyebrow. And the word lachrymist is used to describe someone who tears up a lot (also known by the unscientific term crybaby).

Babies don’t produce tears right away

Actually, while babies cry a lot, they don’t produce tears until they are seven or eight months old, according to the American Academy of Pediatrics. You know who does shed a lot of tears? Studies have found that women cry an average of 3.5 times a month, almost twice as much as men. On average, humans produce 15 to 30 gallons of tears a year.

Crying can be good for you

Some studies have shown a good cry can cause the release of oxytocin and endorphins, chemicals that make us feel better. Crying can also improve people’s sense of well-being by generating social support, researchers have found.

On the other hand, crying can sometimes make you feel worse than if you hadn’t shed a tear

One study found that people who are prone to crying in general more often feel worse after crying during a movie than people who rarely cry.

The two biggest tearjerkers are…

According to Entertainment Weekly, the biggest Hollywood tearjerker of all time is Terms of Endearment, about how a family deals with a cancer diag­nosis. Number 2: Bambi. According to Merriam-Webster, the term tearjerker debuted in 1912, which happens to be the same year the Titanic sank. (The movie Titanic is 16th on EW’s tearjerker list.)

Ever wonder why a cry causes your nose to run?

Excess tears produced by the lacrimal glands flow into your tear ducts. From there, they drain into the nasal cavity, where they mix with mucus to give you a runny nose.

For centuries, people thought tears were created in the human heart

The Old Testament says they’re formed when part of the heart weakens and turns into ­water. In fact, many people cry in the Bible, though perhaps none explains the situation as poetically as David does in Psalm 56:8, when he says to God: “You keep track of all my sorrows. You have collected all my tears in your bottle. You have recorded each one in your book.”

In medieval times, crying was perfectly acceptable, even manly

In the Anglo-Saxon poem Beo­wulf, when Beowulf is killed by a dragon, his warriors were “disconsolate/and wailed aloud for their lord’s decease.” King Arthur was also known to turn on the waterworks.

Tear gas can be used on crowds, but not in war

Speaking of war, tear gas was banned on the battlefield via the Chemical Weapons Convention of 1993, which was spurred by Iraq’s use of chemical weapons in Iran in the 1980s. That said, American law enforcement agencies can still legally use tear gas for crowd control.

Charles Darwin was fascinated by tears

For his book The Expression of the Emotions in Man and Animals, the father of evolution collected observations of South African monkeys and indigenous Australians and compared them with his own kids. Darwin concluded, “We must look at weeping as an incidental result, as purposeless as the secretion of tears from a blow outside the eye … yet this does not present any difficulty in our understanding how the secretion of tears serves as a relief to suffering.”

As we age, production of basal tears slows, which can lead to dry eyes

Women ­going through hormonal changes such as pregnancy or menopause are particularly susceptible. To help the situation, try lubricating eye drops (also called artificial tears) or use warm compresses on your eyes for a few minutes.

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Originally Published in Reader's Digest

Jen McCaffery is an associate editor for Reader’s Digest. Her work has appeared in the New York Times, Prevention, Rhode Island Monthly, and other publications and websites. When she’s not writing or editing, she’s growing veggies or trying to figure out the way home from assorted trails.