Re: MArc runs and trips

From: Rich Travsky (_at_hotmMOVEail.com)
Date: 11/29/04

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    Date: Sun, 28 Nov 2004 21:08:42 -0700

    Marc Verhaegen wrote:
    >
    > :-D

    Don't understand the difference my boy?

    > "Rich Travsky" <" traRvEsky"@hotmMOVEail.com> wrote in message
    > news:41A41712.9DCD2985@hotmMOVEail.com...
    > > Nick Maclaren wrote:
    > > >
    > > > In article <10ppd9o3rtuaubd@news.supernews.com>,
    > > > "John Roth" <newsgroups@jhrothjr.com> writes:
    > > > |>
    > > > |> Horses, for example, cannot run long
    > > > |> distances without suffering heat exhaustion.
    > > >
    > > > Having got home, I can check up on some figures to confirm my back of
    > > > the envelope calculations. We are talking about 150-250 watts (10-17
    > > > kcal/min), plus up to 250 watts (3.5 kcal/min) due to sunlight. The
    > > > difference in conversion is because we are only about 20% efficient.
    > > > At the speeds the current paper is talking about (3-4 m/sec), the
    > > > convection loss is unlikely to exceed 5-10 kcal/min (from many, but
    > > > unfortunately confused, references). We are therefore talking about
    > > > 5-20 kcal/min to lose by sweating, with the latter figure for faster
    > > > running under hotter conditions.
    > > >
    > > > That is 1.25-5 litres/hour of sweat, and we can lose only a few
    > > > litres of body fluid before collapsing. At the lower rate, we might
    > > > keep going for a couple of hours with no liquid; at the latter, no
    > > > more than half an hour or so. That certainly fits with experience.
    > > > We can keep going more-or-less indefinitely if we run slower (or
    > > > walk) or run in cool/cold conditions. But so can horses.
    > > >
    > > > Now, all of that is at fairly fast speeds under tropical conditions.
    > > > A typical small antelope would have collapsed long before we did.
    > > > My point is that many of the papers that talk about our excellent
    > > > extended running abilities ignore the problem that marathon runners
    > > > are provided with drinks along the way, and hominids chasing food
    > > > would have had no such help. Unless we assume that we had already
    > > > developed technologies to carry water.
    > >
    > > It isn't necessarey to run 26 miles to bring down a small antelope...

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