Keeping a Cool Head

The mammalian brain has poor tolerance to increased temperature, but when body core temperature rises during exercise or heat stress, the temperature of the brain can remain at a low level during exercise and under heat stress.

Abstract

The mammalian brain has poor tolerance to increased temperature. However, when body core temperature rises during exercise or heat stress, the temperature of the brain can remain at a lower level, somewhat independent of the rest of the body. In several mammals the cooling of the brain is related to anatomically well-defined countercurrent heat exchangers. Humans lack these distinct anatomic structures, but significant cooling of the brain can nevertheless occur. Such selective cooling of the brain may have important medical implicantions.