I’m wondering if a very long run 2.5+ hours at a steady pace could mirror the effects of parasympathetic overtraining. This is when your heart rate actually DECREASES and you have difficulty pushing it up. It often fools people into thinking they are fit when actually their body is exhausted.
After my good steady long run, I haven’t been able to get my heart rate up for a few days on runs, but I really don’t think my prior training could have caused that. Is one good hard day enough to cause this if I didn’t sufficiently recover after?