Naked Science Forum
General Discussion & Feedback => Radio Show & Podcast Feedback => Topic started by: thedoc on 11/08/2016 20:23:01
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Martin Taper asked the Naked Scientists:
Dear Chris,
This week your program featured the advantages of sweating over redirecting blood to the skin to cool the body in a hot climate. Your guest was half right, and half wrong, about sweating being an advantage.
Sweating is the reaction by which the body uses the latent heat of evaporation to remove heat from the skin surface, and hence the body. It works on the same principle a domestic evaporative cooler.
Heat is required to turn the liquid sweat into vapour to attain the cooling effect, and the sweat evaporating takes the heat from what is the nearest and most conductive medium, the skin. It works a treat in hot dry climates, but when air humidity intervenes, as is the case at the Rio Olympics, it does not. When the air is saturated by moisture, it has no capacity to take on any more moisture from your sweat, and the evaporation cycle stagnates. If your body is sweating in high heat and humidity, you have a worse scenario than if it is not sweating - your body becomes saturated in a hot liquid covered film, which makes you hotter as to its insulating effect of the sweat, heavier as to the water carried by the extra mass of the sweat on you and collected in your saturated clothing, and to add further insult, you dehydrate and tire quicker as you body continues to pump out more water and salts in the form of sweat, in a failed attempt to keep cool.
People like myself, designed for a cool climate, but living in often humid and hot summers, suffer badly, and if I could turn off the my sweating, I would do so eagerly. I also note that native people of hot humid climates, barely sweat at all, and look at ease in the heat and humidity, very much unlike myself.
Sweating is a great advantage in hot dry climates, and a huge disadvantage in hot humid climates, so be careful what you wish for your body to do.
Thanks for a great program. I always look forward to it on ABCRN.
What do you think?