I always joke that when my HRM readings are lower than normal, my horse is doing GREAT, but when they're abnormally high, I just figure something's wrong with the HRM. It happened this past weekend when he was calmly trotting along with a heart-rate of 230 bpm. I checked it by hand (finger on the vein across the jaw), and got 80 bpm. It's not that I don't trust my HRM. I just don't trust it completely.
