What Causes a Fever?

Your body is constantly burning up sugar and other food substances to provide energy. Normally, this burning produces a body temperature of 98.6° F.

But when you're sick, your body tries to fight the sickness by working faster and harder. More blood cells and hormones are produced, your blood circulates faster, and your lungs breathe more quickly.

This helps your body get rid of waste products and poisons resulting from its fight against the disease. Since your body is working harder, it's burning up fuel more quickly, with the result that your body temperature rises to more than 98.6° F — a "fever."

The highest body temperature on record where the patient survived was 112° F.!