It occurs during fever due to the release of cytokines and prostaglandins as part of the inflammatory response, which increases the set point for body temperature in the hypothalamus.
Chills occur when the hypothalamic temperature set point is suddenly elevated.
[2] This could occur due to several causes, including tissue destruction, pyrogenic substances, or dehydration.
[2] The person experiences this period as extreme cold, even though they might have a body temperature higher than normal.
[2] As the body temperature rises and reaches the new set point, chills stop and the person feels neither hot nor cold.