Another piece of the HR story: coach told me to start doing all interval recoveries at 66% power (after 2x20x5s, 6x1x5s, 5x5x5s, pyramids, etc.). This was to improve my rate of recovery since I had been dropped from a break shortly after a 2-minute bridge. So I did that, and tracked how many beats I recovered in the first minute at 66% for given workout. Over a couple weeks, I could clearly see that I was dropping a lot more beats in the first minute than when I started. It had worked, and I was able to quantify it. There's no way to measure that stuff w/out HR.