why body temperature changes when you have a cold?

Question

why body temperature changes when you have a cold?

Answer 1

When you are sick your body will heat up inside in order to try and kill the virus or bacteria that is invading your body. It is best not to lower your temperature, since you will fight off the illness quicker, if possible.

Answer 2

The answer if actually stranger than you might think. Nobody is quite sure why fever occurs. It's clear that your body's immune response affects the thermoregulatory centers of the hypothalamus in your brain, but the usefullness of fever is less clear. Most bacteria couldn't care less if your body heats up a little. Some could even benefit from it! There are possibly a few viruses that cannot thrive at febrile temperatures, but certainly not the majority. Anyway, very high fevers are dangerous, but many doctors will prefer to let mild fevers roll. If there is a benefit, why not take advantage?