Fever results when the body's thermostat is reset higher. Fever is not an illness. It is a sign that the body is fighting infection.
Fever is a helpful response to infection.
If the temperature is set higher, the body feels cold and may send out a signal to the muscles. The muscles begin to shake repeatedly. This involuntary shaking, or chills, makes body heat that helps produce fever. Chills can be constant for up to one hour, or they can come and go. Keep a temperature log when you have a fever.