Check it Out!
Re: Tieing up
In a message dated 2/19/00 9:51:29 AM Pacific Standard Time,
<< Heidi - I'm not sure where you're getting your facts, but Khruschev's
heart rate is 25, I've had him up to 218 bpm. Even considering a fair amount
of error due to heart rate monitor reading, especially at the high range,
is still well over six times the resting heart rate - closer to nine. >>
That's my point, Steph. Horses CAN and DO go off the graph--they can go 6
times OR MORE their resting pulse, and other species cannot. Actually the
range in the study was between 6 and 7 times, as I recall. And yes, there IS
variation among individuals (that's what genetics is all about, and Krushchev
obviously can do this very well). The point here is that horses as a species
DO possess a "natural athletic ability" that people (and other species) do
not, and your horse is an even better example than some.
Of course, you have no clue if his cardiac output was beginning to drop at
that point, since you had no way of measuring stroke volume. However, I
doubt if it dropped a great deal, as once the CO starts to drop with further
increase in HR, it tends to drop fairly precipitously, and you would tend to
see a decline in performance at that point.
I'd also point out that the horses in the study were not fit endurance
athletes, but rather track horses--since endurance athletes have not been
studied in comparison, you don't know how that may affect this phenomenon. I
doubt that it increases the HR at which the CO maxes out (no evidence that we
can just keep going higher and higher on the HR), but there is at least
anecdotal evidence that resting pulses may drop in at least some horses with
fitness, so that could certainly change the ratio to a larger number.
Check it Out!
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