Published on Aug 3, 2018
The average persons core body temperature is 98.6 F (37 C). Human skin is a few degrees colder, being about 35 C (95 F). Heat travels from hot regions to cold regions, according to the Second Law of Thermodynamics. Thus when the wet-bulb temperature, which is the temperature at 100% humidity, reaches 35 C (95 C) the human body can no longer shed heat (sweat no longer evaporates), thus core body temperature rises, and the healthiest person, sitting in the shade, dies in about 6 hours. The rest of us (young, old, medicated, out-of shape, obese, etc…) are SOL at even lower wet-bulb temperatures. Adaptation would require living inside with AC, living in caves, or wearing cooled suits; who wants to do that?
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