About 40 years ago while traveling through the Arizona desert for uninterrupted hours in the summer, in the middle of the day, in a black car with no air conditioning (picture that it was really hot)--I suffered with what was later diagnosed as heat prostration. Prior to that experience, I worked outside gardening, digging post holes, riding horses etc. with no problem. But after that I've tolerated the heat very poorly, flushing from the heat within minutes and unable to sweat to cool off, I would be forced to retreat to the house for relief.