Why do I get a fever when I catch a cold?
For grown-ups: the science
You can get a fever because your body may warm itself up to try to push out the viruses that cause a cold.
A fever happens when inflammation signals from an infection tell the brain's temperature-control center to raise the body's temperature set point. A higher temperature can slow some germs and help immune defenses. The height of a fever alone does not show how serious an illness is. Talk with a health professional if your child cannot drink fluids, seems to have trouble breathing, is very hard to wake or unusually limp, or has a seizure.
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Transcript
When you have a cold, your body can feel warm and toasty. What is happening inside?
Cold-causing viruses can enter your nose or throat. When your body finds them, it tries to push them out.
White blood cells start working against the viruses inside your body. That signal tells your brain to warm your body more than usual.
When you have a fever, viruses may have a harder time growing. Your body uses the heat to try to push them out.
A fever is a sign that your body is fighting the germs that cause a cold. Drink water and get plenty of rest.