Re: [Phys-l] Marylin vos Savant again!

["John Clement" <clement@hal-pc.org>]

But what about the scenario where the person does not sweat properly?

"Anhidrosis is the inability to sweat normally. While this may not sound
like a serious condition, anhidrosis can be life-threatening. When you don't
perspire, your body can't cool itself, which can lead to overheating and
sometimes to heatstroke - a potentially fatal condition."

The original post implied that the person found that a fan seemed to warm
them rather than cool.

The site:
http://www.bt.cdc.gov/disasters/extremeheat/heat_guide.asp
States that fans are not the solution to preventing heat related illness.

So her basic premise was that if the sweat were gone, you would no longer
cool, which is correct.  But normal people properly hydrated in good health
with a good mineral balance should not have a huge problem.

I do think that her comment about the fan being high could cause a problem
is not taking into consideration that people continue to sweat and resupply
the surface water.  So that is off the wall.  But use of a fan would require
continuous hydration and an intake of minterals, and minimal exercise.  Cats
are more intelligent than people as they practically hybernate when the
temperature is high.

I think that she should have picked up on the original posters comments
about feeling warmer and noted that there might be a problem.

So her answer was off the top of the head with a correct idea, but a lack of
research leading to a partially screwy answer.  The CDC recommends cold
showers instead of fans or going to public places with AC.  Unfortunately
none of these work if you have a 2 week power outage after a hurricane.
Fortunately the last Houston hurricane was followed by some cooler weather
as I recall, and our proximity to the power company insured quick repairs.

John M. Clement
Houston, TX

> I can't think of any scenario where Marylin's answer makes sense.
>
> a) If the humidity is high, the fan won't help, but then the
>  person won't get dehydrated, contrary to what she said.
>
> b) If the humidity is not high, the fan helps quite a bit,
>  contrary to what she said.  This is why people buy fans.
>  The amount you have to drink to keep hydrated under the
>  stated conditions, sitting on the porch, is not zero but
>  not unreasonable.
>
> *) Maybe there is some other scenario in which what she said
>  makes sense, in which case her answer is only "mostly" wrong
>  ... but I can't think of any such scenario.  More importantly, 
>  in any case, she should have /told/ us what she is talking 
>  about.  We shouldn't have to guess.
>
> I just got through riding my bike for 30 miles.  It's 105
> in the shade and there's no shade.  Also no breeze.  On the 
> other hand, the humidity is 20%, so it's not hard to keep 
> cool, given enough to drink.  My point here is that I'm a 
> lot cooler when I'm in motion than when I stop.  A fan (or 
> a breeze) helps enormously under these conditions.