The importance of crying

Crying is more complex than just the flow of water droplets; it carries biological, psychological, and sociological significance behind every tear shed.

"No two people shed the same tears." This quote highlights the different emotional struggles individuals face, but it also reveals a hidden biological truth about tears: each person has a slightly different composition and chemical structure in their tears. There are three types of tears, each with its own role and distinct chemical makeup.

Basal tears coat your eyes and are secreted throughout the day. Along with blinking, they form a thin liquid layer over the retina, helping to enhance vision and protect the eye's surface from dust and debris. Tears also carry a small yet significant amount of oxygen and nutrients to the surface of the eyes. They are composed of water, mucus, antibodies, nutrients, and various oils and lubricants that allow the eyes to move smoothly without friction.

Reflex tears help flush out debris, cleanse the eyelids, and protect the eyes from harmful effects—like when you chop onions. These tears contain fewer lubricants but are rich in water and anti-inflammatory molecules.

While the first two types of tears exist in all mammals, emotional tears are unique to humans. They appear in response to strong emotions and play an important role in short-term homeostasis regulation as well as in social signaling. Emotional tears contain higher levels of stress hormones and natural painkillers than other types of tears. They also have a therapeutic function, both biologically and socially—what we often call "a good cry."

Biological importance of tears

Tears, especially emotional tears, have a significant biological impact on a human body. The act of crying lowers blood cortisol levels which strengthens the immune system response, and subsequently reduces the amount of reactive oxygen species in the blood. Additionally, a good cry also elevates the functions of the parasympathetic nervous system, which takes over and can “rationalize” better, which can help exit the “fight or flight” response. This process might play a role in reducing distress and inducing positive emotions in a crying person. Activation of the parasympathetic nervous system is associated with rest, recovery, and relaxation processes. Additional benefit of the parasympathetic nervous system activation is the lowering of blood pressure and heart rate just before crying. Human tears also may contain nerve-growth factor, which is excreted by the tear (lacrimal) gland.

Figure 1: the position of the lacrimal gland. Copyright by Mayo Foundation, https://www.mayoclinic.org/tear-glands-and-tear-ducts/img-20008059

Men are biologically, but also sociologically less inclined to cry. They have smaller tear ducts, have less prolactin and have more testosterone. Prolactin promotes compassion and subsequently tears, while testosterone inhibits crying via several indirect pathways. They cry around 5 times less than women, but the ratio is less pronounced in countries with liberal social views on emotional expression.

Psychological importance of tears

Emotional tears are tied to our mental state. They produce similar results regardless of the emotion they follow, and always calm the person down. Exactly which emotions and events are most likely to conjure tears greatly varies by culture, age, sex and upbringing, but some emotions like helplessness and hopelessness, especially tied to some kind of loss, are universal. Besides tear ducts, crying also involves facial muscle and vocal system activation, as well as elevated breathing rates. The act of crying is often regarded as strenuous, due to the high emotional attachment, but also due to all of the biological processes happening at the time and the activation of aforementioned parasympathetic nervous system. Crying can help alleviate and sort out strong emotions, especially when they arise from multiple sources. If physical pain is present, tears will contain more natural painkillers to combat and relieve the pain, and thus help untangle the conjoined emotions.

Sociological importance of tears

Crying often connects people, and may cause others to be empathetic and compassionate toward you, softening anger or unpleasant emotion that caused the tears to flow in the first place. Since birth, tears and crying are a clear signal to our surroundings that we have not met our needs, like food, comfort and similar. This is true throughout our lives, but in a slightly different form. Crying could also have played a role in the way we as a society evolved, by bonding the untrustworthy individuals into a coherent community.

However, crying is also a big part (or the lack thereof) of cultural and familial setting. Those raised in a more strict environment could have a harder time forming tears, if the society they live in sees them as a sign of weakness or as something unbefitting of public, or even family occurrences. Holding back tears in such surroundings is termed repressive coping and it can weaken the immune system and increase the risk of cardiovascular diseases, hypertension and mental health conditions.

A last look at tears

Tears are more than just water droplets shed for a singular purpose. They are an expression of who we are, both mentally and chemically, and can help maintain homeostasis in both senses. There is still an ongoing research conducted on the benefit, but also on the cause of tears. How and what we cry for can be a direct sign of our mental state and a diagnostic marker of some mental illnesses. Especially interesting are the people who either cry too much or aren’t able to cry at all, due to their inability, or excess ability to trigger certain neurological pathways and brain regions.

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