Re: AAH: humans long-distance runners?
Gerold Firl (email@example.com)
1 Dec 1994 13:20:38 -0800
In article <firstname.lastname@example.org> email@example.com (Jim Little) writes:
>I just have to jump in here, 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
True. But that is exactly what humans do; we generate a thin layer of
moisure all over our body. Of course, some does drip-off, and that is
wasted, as you say, but most of it evaporates, which results in cooling.
Our cooling system is not optimally *efficient*, just extremely
*effective*. It rejects huge amounts of heat. A god, or an engineer, would
try to design a more efficient system; evolution just produces one that is
>A dog (and many other animals) can cool its entire body just by
>panting (with associated cooling by evapouration present in its
At 100 degrees fahrenheit a dog can cool its entire body by panting, if it
lays quietly in the shade to minimise the amount of metabolic heat
produced. A man can run at that temperature.
>The human system of sweating is very wasteful and poorly
>adapted to its function.
Not really. It is somewhat wasteful, but very well adapted to its function.
It gives us a capability which no other animal can match.
>I can give you a reason for an aquatic hominid to sweat as prodigiously as
>modern humans do, to eliminate excess salt from the body.
I haven't read morgan, but from the comments I've read it appears that she
doesn't mention that the human sweat ducts have a salt-recovery system
which actually re-absorbs salt from sweat as it is secreted from the
sub-dermal glands and passes to the surface of the skin. (See Guyton,
Disclaimer claims dat de claims claimed in dis are de claims of meself,
me, and me alone, so sue us god. I won't tell Bill & Dave if you won't.
=-=-=-=-=-=-=-=-=-=-=-=-=-=---- Gerold Firl @ ..hplabs!hp-sdd!geroldf