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What Is a Cold?

It's called common cold. The common part is right on: it's the most frequent infection across all U.S. age groups. Most adults have 2-4 colds per year and children can have up to 10 per year. The cold part isn't so accurate. People used to think a cold came from getting a chill. Now we know that isn't how it happens.

What does happen is that you catch a virus from another person. This often happens by touching a contaminated surface and then touching your eyes, nose, or mouth. You can also catch a cold by encountering secretions sneezed into the air.

A cold begins when one of several different kinds of cold virus attaches to the lining of your nose or throat. Your immune system sends white blood cells out to attack this germ. Unless you've encountered it before, the initial attack fails and your body sends in reinforcements. Your nose and throat get inflamed and produce lots of mucus. With so much of your energy directed at fighting the virus, you feel tired and miserable.

What Causes It?

There are approximately 200 viruses that can cause a cold. Rhinoviruses and there are more than 100 subtypes - cause up to half of all colds.

While getting a chill does not cause a cold, there are factors that make a person more susceptible to attack by cold viruses. These include excessive fatigue, emotional distress, allergies involving nose and throat symptoms, and the middle phase of the menstrual cycle.