Humans are unique in the animal kingdom. It’s not at all unusual for an animal to vocalize pain or emotion, but humans are virtually the only animals to cry tears to express an emotion such as sadness or happiness.
Lacrimation, as the doctors call it, can also happen in reaction to an irritant such as a particle of dust landing in your eye or a reaction to the chemicals released when slicing open an onion.
(More on the types of tears we cry in just a moment.)
The lacrimal gland (see illustration below), which sits between your upper eyelid and eyeball, produces tears. Even when you’re not “crying” the gland produces tears to keep your eyes from drying out.
Every time you blink these tears get spread out over your eyeball and then drain through the lacrimal punctum (the tiny little dot or hole you can see in the inner side of your bottom eyelids closest to the nose, see the illustration below).
But if there are too many tears to effectively drain through the lacrimal punctum—either because of an irritation or a crying jag—the tears will flow over your bottom lids and fall down your cheeks.1
Humans cry three kinds of tears
The human body actually produces three different kinds of tears:
1. Basal tears:
Basal tears are the kinds of tears your body makes to keep your eyes from drying out. Around a gram of basal tears are produced by your body every single day. They’re secreted into your eyes and coat your eyeballs every time you blink.2
2. Reflex tears:
Reflex tears, as the name implies, are produced when your body is reacting to some type of irritant. Anything from wind to smoke to onions can cause your lacrimal gland to start pumping out reflex tears to protect your eyes.
3. Emotional or “psychic” tears:
Emotional or “psychic” tears are the type of tears that make humans so unique. The human autonomic nervous system plays a role in these largely mysterious tears which can be triggered by any sort of strong emotion including sadness, happiness, estrés, or pain.
Here’s how psychic tears were explained in The Independent:3
“… [T]here is an area of your brain specifically to deal with your emotions, called the limbic system (specifically the part of it called the hypothalamus), which is hard-wired into your autonomic nervous system (that’s the part you don’t have any control over).
This system, via a neurotransmitter called acetylcholine, has a degree of control over the lacrimal ‘tear’ system; and it is this tiny molecule which then stimulates tear production.
So in short, your emotional reaction … triggers your nervous system, which in turn, orders your tear-producing system to activate.”
Crying is MORE than just tears
Of course crying isn’t just tears rolling down your face. Your heart rate usually goes up when your cry psychic tears. And many folks break out in a sweat when they cry.
And then there’s the sensation that many people describe as “having a lump in my throat.” This feeling, technically called a globus sensation, is caused by the strain caused to your throat muscles.
When you cry, the opening in your throat that allows air to pass from your larynx to your lungs (known as your glottis) becomes enlarged.
When you swallow, your glottis closes, but when you cry your body enlarges the opening to let in more oxygen. It’s this fight between trying to open and close your glottis that leads to muscle strain and the feeling of a lump in your throat.4
Crying may have developed as a social survival mechanism
Some experts theorize that crying tears ay have developed as a sort of social survival mechanism. When we cry our faces literally look sad which may trigger a supportive reaction by those observing it.
The American Psychological Association (APA) described it this way:5
“‘Tears add valence and nuance to the perception of faces,’ says the study’s lead author, Robert R. Provine, PhD, a professor of psychology and neuroscience at the University of Maryland, Baltimore County.
Tears become a sort of social lubricant, he says, helping to ensure the smooth functioning of a community by helping people communicate.”
En otras palabras, when you shed tears you’re signaling vulnerability. You are automatically less of a threat and this can trigger feelings of empathy in those around us making your personal and social relationships stronger.
One researchers, Oren Hasson, PhD, explained it as follows:6
“My analysis suggests that by blurring vision, tears lower defenses and reliably function as signals of submission, a cry for help, and even in a mutual display of attachment and as a group display of cohesion.”
Are “healing tears” a real thing?
The chemical makeup of tears is interesting. The tears you shed in response to an intense emotion, psychic tears, are chemically different from the other two types. Psychic tears have a high concentration of a stress-related chemical called adrenocorticotropic hormone (ACTH) in them.
Some experts believe that an important function of crying is to help your body rid itself of these excess stress chemicals so you can become calmer and more relaxed.
You’ll also find a neuropeptide called nerve growth factor (NGF) in your tears. NGF plays an important role in the development and survival of neurons, particularly sensory neurons involved in transmitting pain, temperature and touch.7
On the potential healing aspects of tears Provine said:8
“Several lines of evidence suggest that the NGF in tears has medicinal functions. The NGF concentration in tears, cornea, and lacrimal glands increases after corneal wounding, suggesting that NGF plays a part in healing.
More directly, the topical application of NGF promotes the healing of corneal ulcers and may increase tear production in dry eye … Although more of a scientific long shot, I suggest that tears bearing NGF have an anti-depressive effect that may modulate as well as signal mood.
Non-emotional, healing tears may have originally signaled trauma to the eyes, eliciting caregiving by tribe members or inhibiting physical aggression by adversaries.
This primal signal may have later evolved through ritualization to become a sign of emotional as well as physical distress.
In this evolutionary scenario, the visual and possibly chemical signals of emotional tears may be secondary consequences of lacrimal secretions that originally evolved in the service of ocular maintenance and healing.”
4 fascinating facts about crying
Why humans shed tears is still a question shrouded in mystery, but there are some intriguing facts worth learning. Mental Floss recently shared several of them:9
1. Crying ultimately makes you feel BETTER
You’ve probably heard some people refer to a crying session as a “good cleansing cry.” Well, it turns out those folks are onto something.
An interesting study published in the journal Motivation and Emotion revealed that while crying makes the person crying feel worse initially, eventually the act of crying will make raise your mood and make you feel better.10
For the study researchers had 60 people watch an emotional movie and assessed their moods immediately after the viewing and then again in 20 minutes and then 90 minutes later. Those who cried during the film had significantly increased negative moods right after while the tearless folks didn’t experience any mood changes.
By the next measurement, the criers’ moods had returned to baseline but, interestingly, by the final measurement their moods had not only recovered but also were enhanced compared to measurements taken before watching the film.
So it turns out a god cleansing cry really CAN boost your mood… eventually.
2. You can keep onions from making you cry
An irritating gas called lachrymatory factor (LF) is released from onions when you slice them. Japanese researchers developed an onion that lacked the enzyme necessary to produce LF, and therefore wouldn’t cause tearing, but it also altered the beneficial sulfur-containing compounds in the onion.
So while the fact that onions make you tear up is a bit inconvenient, it’s also a reminder of the many potent health compounds they contain. But did you know that you can stop onions from irritating your eyes and causing you to cry?
The World’s Healthiest Foods explains how:11
“Use a very sharp knife and always cut the onions while standing; that way your eyes will be as far away as possible. Consider cutting onions by an open window. If cutting onions really makes you cry, consider wearing glasses or goggles.
Chill the onions for an hour or so before cutting; this practice can slow down the onion’s metabolism and thereby lessen the rate of LF gas production.
Cutting onions under cold, running water is a method that is often used to cut back on eye irritation, but it’s a method we view as a second-best choice since some of the nutrients found in onion can be lost into the flow of water.”
3. Tears can be a social lubricant that helps you win negotiations
Earlier I explained how tears may have once been a survival mechanism and that experts say they can strengthen social relationships by showing your vulnerability. You can use the natural human instinct of empathy to your advantage.
Researchers say when you reveal sadness, including crying, during a negotiation it could help you get your way. But three’s a big catch—or actually four of them—according to the study published in The Journal of Applied Psychology.
The person observing the crying had to:12
- Perceive the crier as lower power
- Anticipate a future interaction
- Perceive the relationship as collaborative
- Believe that it was inappropriate to blame others
4. Over 45% of women (and many men) have cried after sex
It turns out crying after sex is quite normal. Research suggests nearly half of women have cried after sex at some point in their lifetime.13 Separate research has found that it’s not uncommon for men to have shed after sex either.
Crying after sex is technically called postcoital dysphoria, or PCD. Experts say it may be caused by fluctuations in our hormones that occur during and after sex. It may also be due to the intimate nature of sex, which allows people to express emotions they’ve been keeping bottled up.
Striking microscopic views of tears
Photographer Rose-Lynn Fisher wanted to know what dried human tears look like on a microscopic level. Over several years she collected more than 100 tears from herself, volunteers and even a newborn baby. She photographed the dried tears under a microscope and released them in a project called “Topography of Tears.” .
The result was a beautiful collection of strikingly different images, many resembling large-scale landscapes. Fisher described them as “aerial views of emotion terrain.”14
She explained to Smithsonian magazine:15
” … Tears are the medium of our most primal language in moments as unrelenting as death, as basic as hunger and as complex as a rite of passage … It’s as though each one of our tears carries a microcosm of the collective human experience, like one drop of an ocean.”
Tears shed while laughing, feeling grief, tears of change, onion tears and others all appear remarkably different.
As the saying goes, a picture is worth 1,000 words, so here are a few:
1, 3 Independent September 18, 2014
2, 14, 15 Smithsonian November 19, 2013
4, 9 Mental Floss November 6, 2015
5 American Psychological Association February 2014, Vol 45, No. 2
6 Evolutionary Psychology 2009; 7(3): 363-370 [Free Full-Text PDF Report]
7 Lister Hill National Center for Biomedical Communications, Genetics Home Reference, NGF
8 Brain Pickings
9 Mental Floss November 6, 2015
10 Motivation and Emotion August 23, 2015
11 World’s Healthiest Foods, Onions
12 J Appl Psychol. 2015 Nov;100(6):1847-71.
13 Sexual Medicine December 2015, Volume 3, Issue 4, pages 235-243
16 Rose-lynnfisher.com, The Topography of Tears
New York Times bestselling author Dr. Mercola graduated from the Chicago College of Osteopathic Medicine in 1982. And while osteopaths or D.O.s are licensed to prescribe medication and perform surgery just like medical doctors (M.D.s), they bring something extra to the practice of medicine.
Osteopathic physicians practice a "whole person" approach to medicine, treating the entire person — rather than just the symptoms. Focusing on preventive health care, D.O.s help patients develop attitudes and lifestyles that don't just fight illness, but help prevent it too.
Dr. Mercola is passionate about natural medicine and strongly believes that the current medical system is largely manipulated and controlled by large corporations whose primary focus is profit. His website, Mercola.com, which started as a small hobby interest in 1997, has now grown to today’s number one natural health website educating and empowering millions to take back the control over their own health.
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