It may have been mentioned already, but another factor I like to keep in mind in addition to average and max heart rate is the recovery rate as in how fast your heart rate decreases once you stop. I did the simple test this guy describes and was pleased to find that at 62 in addition to an average BPM of 145ish and a peak of 165ish out on the trails on a regular basis, I am averaging around a 45-50BPM decrease in the first minute after stopping exertion.