Perspiration Vapor Lightens Near-Skin Air, but Hinders Human Evaporative Cooling in Arid Heat

Sweat May Cool the Body Less Than Expected in Dry Heat, Study Finds

A new study finds sweating in dry heat may cool the body less than expected, exposing a flaw in heat-safety models used for over 70 years. The post Sweat May Cool the Body Less Than Expected in Dry Heat, Study Finds appeared first on StudyFinds.

New sweating discovery reveals hidden limits of body cooling

The purpose of perspiration was a mystery in 1775, when English physician Charles Brian Blagden and a few inquisitive friends experimented on themselves by spending time in rooms heated to over 230° Fahrenheit.

The science of sweating still holds surprises—including how still, dry air can hinder cooling

The purpose of perspiration was a mystery in 1775, when English physician Charles Brian Blagden and a few inquisitive friends experimented on themselves by spending time in rooms heated to more than 230°F (110°C). While the temperatures were hot enough to cook raw meat placed in those rooms, Blagden noted how human bodies resisted the heat. Their core body temperatures remained nearly constant as sweat poured out and evaporated.

Perspiration vapor lightens near-skin air, but hinders human evaporative cooling in arid heat

Abstract Sweat evaporation is the body’s primary cooling mechanism, yet the physical factors governing it are not fully understood. We identify a “dueling buoyancy” effect in the context of the human body, in which perspiration vapor reduces the near-skin air density, counteracting the downward flow driven by cooling of warm air upon contact with the skin. In hot, arid, stagnant environments, this opposing buoyancy suppresses free convection and…