Re: [Paddlewise] Body type and hypothermia (was fatal Kayaking mishap in the Florida

From: <timbre_at_best.com>


> At 08:10 PM 1/2/01 -0800, you wrote:
> >Those who are
> >out of shape and overweight do not control their blood vessel dilation 
> >very well.
> 
> 
> wait a minute there, sparky.  you aren't saying, are you, that all 
> overweight people are out of shape???  now, THAT is a myth!  there are 
> plenty of fat and fit people out there, to wit:
> 

If you re-read my post, I mention out-of-shape and fat as well as relatively
fit and overweight.  I know amateur athletes across the whole spectrum.

Doug's comment on my post mentions:

> Good points, Mike. My most cold-resistent moments have been during times
> of maximum physical conditioning (kayaking specific) combined with a bit
> of extra weight I carry around on my relatively stocky frame. 

I found that as my weight increased over the last couple of decades (slowly,
then I met Amie) my ability to handle cold in Nordic skiing improved, as did 
my overall "toughness" and ability to recover.  My earlier "marathon runner"
frame (approx 8% body fat - measured) just didn't do it.  Fat is necessary
for the cold.

> One thing
> to bear in mind: I have a number of marine mishap reports from the cold
> waters of BC, and by far the most incredible stories of survival come
> from examples of hugely overweight yet relatively fit fisherman, who
> survive for numbers of days, not number of hours, on upturned hulls in
> stormy seas. Amazing.

The key is that they are relatively fit.  This allows the body to develop the 
ability to control their heat better through controlling blood flow to the outer
skin.  Under these conditions, the fat _can_ act as an insulator.  A true
couch potato wouldn't likely have the same survival likelyhood.

Blood flow to the outer skin can carry an incredible amount of heat away from 
the core.  Likewise, rescuing a hypothermic person, especially from cold water 
immersion, means keeping them at rest.  Getting their blood flowing in a rescue 
situation can reverse the heat flow.  The now-cold outer layers will result in cold 
blood being pumped back into the core, which can result in sudden death.  
Blood in your body can be compared to radiator fluid in your car.

Mike



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