Dr Skinner wrote:
This is a similar question to that of those funny foil
> blankets people wear at the end of the London Marathon. I assume they are
> supposed to prevent people cooling too quickly (why ?) but surely a woollen
> blanket would be better. We are not heat lamps radiating heat; we are hot
> bodies convecting and conducting to the environment.
>
We lose heat by conduction, convection, radiation and evaporation.
The amounts depend on the circumstances.
The foil blankets are probably over- rated and I agree, a nice woolly (warm
when wet with sweat too) and a windproof layer would work better.
The foil is windproof though.
Only real advantage is that foil is light - so good for carrying for
emergent situations - not necessary when have families/friend available to
watch one puke with pain after 26 miles :-)
Jel
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