Re: Heartrate Threshold

[Tivers <Tivers@aol.com>]

In a message dated 98-05-19 13:52:53 EDT, CMKSAGEHIL writes:

<< Maybe I have missed it in this thread, but the bottom line about heartrate
thresholds is that the threshold is the point at which the heart can no longer
refill properly between strokes, hence the stroke volume goes down, hence the
cardiac output actually decreases.  As someone pointed out, the next step up
is fibrillation... >>

"Heartrate threshold" means, to me, the heartrate at which the horse enters
the lactic acid threshold--4 mmol/L. To that point, heartrate increases are
near-linear with speed. Beyond that point, since the oxidative system cannot
keep up, speed rises more quickly than heartrate--power generated by the
anaerobic system.

ti