Re: Shirt color vs. heat [was Re: the 2003 Cali-MUni week-end thread.]
>On Thu, 18 Sep 2003 14:49:11 -0500, Ken Fuchs <firstname.lastname@example.org>
>>Actually, real dark colors, especially black, are the best if you want
>>to stay cool. The dark colors absorb heat better which evaporates the
>>sweat better and thus cools our bodies better.
email@example.com (Klaas Bil) wrote:
>So because the shirt gets hotter it cools us better?
The heat the shirt absorbs is transfered to the evaporating sweat. Plus
some of the body heat of the shirt wearer is also transfered to the
evaporating sweat, thus cooling their body.
>And if I want to cool down I should stay near a heater so that my
>sweat evaporates more?
Yes, if your body loses more heat through evaporation (plus heat loss
through radiation of your body and clothes) than your body gains by
being closer to the heater. There should be an optimal distance from
the heater (probably not close to it) to achieve maximum cooling effect.
(Fortunately, we can’t choose to be the optimal distance from the Sun.)
Why would one have the heater on, if one is sweating? I’d recommend
turning off the heater and turning on the air conditioner (if there is
one) or the fan. Of course a moving unicyclist simulates the action of
a fan by moving through the air.
Note that there are two ways to increase evaporation, more heat and more
Also, note that cycling shorts are almost always black, so they absorb
enough heat to evaporate the sweat and thus cool the rider.
Unevaporated sweat cools the body a tiny fraction of an equal amount of
If you regularly soak a light colored t-shirt with sweat on your rides,
you would be cooler if you wore a black t-shirt (or less effectively a
dark color). Note that is more effective on sunny days.
If you occasionally break a sweat wearing a light colored t-shirt with
sweat on your rides, stick with the light colored t-shirt or better yet
ride harder, sweat profusely and wear a dark t-shirt.
Of course, sweat salts will show up better on the darker t-shirts. Wear
your sweat salts proudly!
Ken Fuchs <firstname.lastname@example.org>