If you’ve ever tasted your tears, you may have noticed how salty they are. Tears are salty because they are made from water from our body that contains electrolytes (salt ions).
What Are Tears Made Of?
Tears are 98% water. The remaining 2%, which is responsible for the salty taste, contain:
- Oils
- Salt
- More than 1,500 proteins
Tears and all of our other body fluids are salty because of electrolytes, also known as salt ions. Our bodies use electrolytes to create electricity that helps power our brains and move our muscles.
Electrolytes contain:
- Sodium (which accounts for the saltiness)
- Potassium
- Chloride
Where Do Tears Come From?
Tears emerge from your lacrimal glands, which are under your upper eyelids and above your eyes. They spread across the surface of your cornea and drain from your eyes through tear ducts in the corners of your lower eyelids.
Then, they drain down your nose and mix with mucus. That's why you get a stuffy nose while crying and why your nose sometimes feels less clogged after a good cry.
One person produces 15 to 30 gallons of tears per year.
How Do Tears Function?
Tears exist to protect and nourish our eyes, shielding them from debris, viruses, and bacteria. Every time you blink, your tears are helping you hydrate and clean your eyes.
The water in tears keeps your eyes moist and healthy. It contains minerals and vitamins that nourish and boost the cell function of the surface of your eye, the epithelium.
Although tears look like they’re mostly made of water, they’re quite complex. Our tears are made of three layers, all of which have a specific purpose:
- The mucous layer, which attaches the tear to the eye. Without this layer, you may get dry spots on the surface of your eye. The drier your eyes, the more likely you will develop eye infections.
- The aqueous layer, which is responsible for hydrating your eye, protecting your cornea, and keeping bacteria out. It’s the thickest and saltiest layer.
- The oily layer, which keeps the surface of your tears smooth so they’re translucent. The oiliness also prevents the other layers from evaporating.
What Are the Three Different Types of Tears?
The saltiness of your tears depends on what type of tears you’re shedding. There are three different types of tears:
- Reflex tears, which protect your eyes from irritants such as onion fumes and strong odors. Reflex tears, along with basal tears, are the saltiest types of tears, since both types are meant to keep your eyes healthy. Unlike basal tears, reflex tears only wash irritants away and can’t coat the surface of your eye.
- Basal tears, which cover the surface of your eye. They’re always there to shield your eyes from potentially dangerous substances in the air and to make sure your eyes don’t dry out. Basal tears help prevent conditions such as dry eye syndrome.
You produce fewer basal tears as you get older, so dry eyes are more common in older people, especially women after menopause.
- Emotional or psychic tears, which is what we usually think of when we talk about tears. Your body makes them when you feel intense emotions. Emotional tears are the least salty of all tear types. That’s why your eyes get puffy when you cry. Water naturally moves to the saltier areas of your eye.
Crying can make you feel better because emotional tears contain hormones and proteins not usually found in other types of tears. These hormones, such as prolactin and leucine enkephalin, can help reduce stress and boost mood.
Emotional tears also serve as social cues to others. Even when people can’t see you crying, they can actually smell your tears.
In one study, researchers collected tears from women who were watching a sad movie. Male participants could not tell the smell of real tears from a saltwater solution. But the men who smelled the real tears rated women’s faces as less sexually appealing. They also had lower levels of sexual excitement, according to MRI and saliva tests.
Do Tears Change During Sleep?
Tears change when we fall asleep. When you’re asleep, your tear ducts add less protein and water to your tears but boost antibodies. Cells that fight infection also move to your eye.
Your tears may also mix with oils, mucus, and skin cells while you sleep to make crusts in the corners of your eyes. Since you don’t blink when you’re sleeping, this mixture hardens in the corners of your eyes. It stays there until you wake up and blink.