Body temperature regulation. Artwork based on a thermogram of the human body under different temperature conditions. It is warm at left and cold at right. Temperatures are colour-coded: red (37 degrees Celsius, normal body temperature), peach (37-36 degrees), light pink (36-32 degrees), dark pink (32-28 degrees), light blue (28-25 degrees) and dark blue (below 25 degrees). Even under normal conditions the extremities are cooler. When the body is cold, however, it diverts heat to the core region, incorporating the brain and chest organs, in order to save energy while protecting the vital organs. Death occurs when the core body temperature drops below about 32 degrees.