Crying is an inseparable part of human emotions. It is defined as creating tears in response to different emotions (anger, happiness, sorrow). According to statistics, women cry in average between 30 and 64 times, and men between 6 and 17 times per year.
There are several types of tears: basal, which are constantly present in the eye and protect it from drying; the other type are reflex, which protect the eye from various irritants (smoke, dust, strong wind) ; the third type of emotional tears. But why are tears our body’s response to emotion? One of the possible explanations can be found in evolution. Vision is our primary sense and is very important for our survival and interaction with others. Tears drain any eye injuries (they are salty to enhance the disinfectant effect) and allow the ejaculation of a foreign body from the eye. Therefore, it is very likely that the vision, through evolution, has been so important that when a person is sad, the body, just in case, responds in making tears as a form of protection. What’s interesting is that all these types of tears have a different composition. The first two types consist of mostly water, while the third type, emotional, contains water and various hormones, but also leucine-enkephalin. It is believed that this compound, leucine-enkephalin, is responsible for why people cry. Namely, it is a substance that suppresses the feeling of pain and improves mood; the effects are similar to morphine (they work with the same mechanism), only a lot weaker because the amount of leucine-enkephalin that is excluded is small. For this reason, this substance is considered responsible for making people feel better after a good crying session. Although the crying mechanism isn’t still sufficiently explored, it is possible that its role is just to make a person feel a little better during the hard times.
It is interesting that there are so-called “crying clubs” in Japan, where group sessions are organized during which sad movies are played or visitors read sad books which cause them to cry.