[RC] Heart Rates and Fitness - Bruce Weary DCHi Dave--That is a very good question, and I think there are several variables to consider. First, what is your gelding's RHR? If his is naturally higher, it will likely be higher during similar work and during a CRI, even if he's fitter. He may have a smaller heart and his stroke volume requires more beats to move the same amount of blood as your mare. The rest of his tissues are, no doubt, fitter than hers--better bone and ligament density and joint stability. Denser muscle, better water and electrolyte metabolism, sweating mechanism and heat tolerance. He is likely better able to shift fluids to different body compartments than your mare can right now. The heart rate, although it is influenced by the other factors I mentioned previously, gives a relative view of the horse's tolerance to work, not an absolute one. In other words, your gelding by be feeling better at a pulse of 60 than your mare will at 50, given her present level of conditioning and naturally low heart rate. Your mare may indeed be a better overall candidate once she has had the time to adapt to the demands of exercise that your gelding has. Anyone else have any insight on this? I am just guessing and could be wrong. Dr Q, often wrong, but always sincere.
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