A single tear has nearly one thousand different constituents that make up the highly complex biological fluid. Your body creates tears to keep your eyes from drying out, but it may have to work overtime when a particle is in your eye or your child says, “I do.”
Tears of emotion contain hormones that tell your body to release cortisol, the stress hormone. When you feel emotions like joy or fear, cortisol builds up, and crying provides a physiological release. If you don’t cry, your body may look for other ways to process the hormones, like hyperventilating or having a panic attack. Exercising or deep conversation are also ways to release cortisol, but sometimes a good, hard cry is simply enough for your system.
Humans may be the only animals who cry for emotional reasons, and evolution points to the benefits of showing vulnerability as intensely social beings. One may weep when sad or feeling helpless or cry because you’re empathizing with someone else’s loss or joy. It helps people bond and develops trust with each other.