We’ve all stared up at the ceiling as congestion makes it impossible to fall asleep at night. Or felt like we were drowning in piles of tissues during a cold. In these moments of misery, we find ourselves wondering: why do we have mucus anyway?
Mucus is vital to our well-being. Without it, we’d risk encountering more pathogens, damaging our lungs, and burning the walls of our stomachs.
It covers body parts that can be exposed to the outside world without the protection of skin. Made of water, sugars, and proteins, it’s sticky and slimy texture hydrates and protects. Quartz talked to Sydnee McElroy, a family physician practicing in Huntington, West Virginia, and Michael Ellis, an otolaryngologist at the Tulane University School of Medicine, to understand about how mucus helps different parts of the body.
- Nose: Mucus traps pollen, soot, and even viruses or bacteria before reaching our lungs. With the help of tiny fiber-like hairs in our nose, it migrates down to our throats, where we swallow it multiple times a day. Mucus also preps air we breathe through our nose for our lungs by making it warmer and adding water vapor.
- Lungs: Like the nose, the lungs contain small amounts of mucus to keep them hydrated and protect them from particles and pathogens the nose may have missed.
- Gut: Our stomachs are lined with a thin layer of mucus to prevent digestive acid from harming the tissue. Mucus that lines our intestinal walls provides a barrier from bacteria that may be harmful and helps beneficial bacteria provide us with nutrients.
- Vagina: Mucus works to keep the vaginal canal hydrated, and thickens or thins depending on where a woman is in her ovulation cycle. In the days leading up to ovulation, women produce (paywall) larger amounts of watery, clear cervical mucus, which helps sperm reach an egg to be fertilized.
The color of your mucus is important: When mucus is green or yellow, it can sometimes—but not always—indicate that the body is trying to fight off an infection. Certain white blood cells called neutrophils contain a protein that helps them break down pathogens. This protein, called myeloperoxidase, contains iron; in mucus, it appears green. Persistent green mucus could mean you have an infection.
If you notice yourself feeling nasal congestion, before taking medicine you should make sure you’re properly hydrated. Every day, we produce the same amount of mucus in our sinuses. We get congested because there isn’t enough water to make our mucus thinner. Drinking more fluids can help your sinuses can produce more watery secretions to make your mucus thinner.
Most of the time, our mucus works thanklessly to keep us healthy and happy; when it bothers us, we disregard it as annoying. But the truth is, we’d be even more miserable without it.