This condition is discussed in more detail in a subsequent section of this article. When this occurs, the body attempts to increase heat production and reduce heat loss. This is done in part by constricting the cutaneous blood vessels, resulting in a decreased flow of blood to the skin. Consequently, the patient may experience chills, feel cold, and may shiver, despite the increased internal body temperature. The pyrogens are synthesized in large quantities in the leukocytes when infectious agents are present in the body.
Pyrogens stimulate the hypothalamus to raise the body's internal temperature, resulting in a fever.
Because a high body temperature inhibits the growth of bacteria and viruses, a fever allows the immune system to more effectively neutralize these pathogens.