There are both physical and physiological differences between men and women, which have led researchers to wonder whether women are at an inherent “advantage” or “disadvantage” relative to men with regard to thermoregulatory responses in athletic events, particularly those of long duration.  Women, on average, are physically smaller than men, which results in larger surface area-to-mass ratio (i.e., heat is generated based on body mass and dissipated based on surface area); however, it is unclear whether these size differences are quantitatively relevant across “human-relevant” sizes.  Reproductive hormones have influences on thermoregulatory and volume regulatory responses.  For example, estradiol promotes heat dissipation via both central effects on hypothalamic warm-sensitive neurons and peripheral effects on blood flow and sweating responses.
 
In previous decades, research in human thermoregulation in which sex was considered as a biological variable was minimal to absent.  Those historical reports that did mention sex differences often started with the assumption (based on anecdotal or poorly controlled data) that women are at an inherent disadvantage with regard to exercise thermoregulation in hot environments.  More recent, well-controlled studies indicate minimal differences between the sexes in terms of thermoregulatory mechanisms in scenarios that are relevant to the majority of athletic, military and industrial scenarios.  This talk will review the evidence for sex differences in thermoregulation during exercise, and discuss practical implications for athletic endeavors.