Re: Runners and horses

["Beth Glace" <lb@nismat.org>]

Hi Robyn and Lif,
just to maintain accuracy I thought I'd correct some misinformation in 
the Trail Blazer article re: human physiologic capacity.  If we are 
going to start throwing numbers around let them be in the ball park.  I 
am not sure who wrote the 1995 article, but its references to human 
values way underestimate capacity.  
> Highly trained Olympic-caliber athletes can only
> increase this pumping rate by approximately two times, from 5 liters
> of blood per minute at rest to 10 liters during peak activity.
The highest recorded cardiac output values for humans are above 30 
liters per minute, with good athletes typically in the 15-20 liter range.

> An Olympic athlete performing at top speed can increase oxygen
> consumption by about 10 times the amount needed at rest; the
> average horse can increase their average comsumption by an amazing
> factor of 35 times. 
No, no.  A very unconditioned human may only be able to increase 
oxygen consumpion from rest [3.5 mls/kg] to 35 mls/kg at maximum 
[10 fold].  Well trained athletes can increase oxygen consumption 20 -
25 fold, to 70-95 mls/kg.  

> at full effort with an air exchange of about 35 liters per minute.

Whoa.  WAY off,  I typically measure ventilation at 150-200 liters per 
minute at maximal exertion.  
I agree that equine capacity is greater than human's, but my guess is 
that overall it is about twice that of man.
Regards, to all,
Beth Glace, MS
Sports Nutritionist, Research Assoc
NISMAT
Lenox Hill Hospital
NY, NY