Re: AAH: humans long-distance runners?

Phillip Bigelow (
Thu, 1 Dec 1994 18:15:50 GMT (Jim Little) writes:

>...all sweating buckets does is remove buckets
>of essential moisture from the body which must then be replaced. Water
>that runs off the body in rivers does not cool any better than a very thin
>film. A dog (and many other animals) can cool its entire body just by
>panting (with associated cooling by evapouration present in its

Exactly. And, pound for pound, a dog looses a similar amount of
"essential moisture" from panting as a human does from sweating.

> the human system of sweating is very wasteful and poorly
>adapted to its function.

You have fallen into a "logic trap" here. If the human system of
sweating is very wasteful, as you claim, then it is _also_ a very wasteful
process if the purpose of the sweat glands is to remove excess salt from the
body, because essential moisture is lost none-the-less. Salt removal glands
on mammals remove salt from the body in much greater concentrations than
does sweating in humans, and these glands do it using much less water than
do humans. Besides, humans have no other form of cooling system other than
sweating. Therefore, the main purpose of sweating _must_ be for evaporative

Indeed, sweating in humans _does_ remove salt from the system, but this may
be just another instance where evolution is killing two birds with one
stone. Since sweating is the only major thermo-regulatory mechanism in
humans, what better way to remove a little excess salt at the same time?
The plumbing was already installed.