Originally Posted by wphamilton

And, since you're in about the same age range as I am, I'll bet that like I did you designed your volume and intensity around what your body could absorb rather than performance markers such as cardiac drift or time near threshold etc etc. We have to live in the range between the "comfort zone" too relaxed to produce gains, and performance goals that produce injuries or excessive recovery periods. Sometimes those lines are pretty close together, and "cardiac drift" is going to provide no meaningful insight on where the lines are. At best I'd use it as an indicator that I've neglected or overlooked something.