Why is it that our bodies can stand dry heat over humidity?
This is because our bodies are less efficient at losing heat in higher humidities. We cool down by sweating, and the sweat evaporates from our skin carrying the excess heat away with it. In dry air (low humidity) has very little moisture in it, and so water in our sweat can evaporate into the surrounding air much more readily (i.e. there is a concentration gradient of high moisture on our skin, to low moisture in the air and the steeper the gradient the greater the rate of water evaporation from the skin, therefore increasing the amount of heat that can be ‘lost’ to the environment). If there is high humidity, then there is much more moisture in the air and the concentration difference between the sweat on our skin and the water vapor in the air will be greatly reduced, thus reducing the steepness of the concentration gradient between skin and air, thereby reducing the amount of heat we can lose from our bodies. This makes it an unpleasant environment to be in. For similar reasons we f