I think it is what it is! Your recovery HR and RHR are telling, I think, of the kind of shape you are in. I've wondered about this often myself because my MHR (I'm fast approaching 50) is in the 190's. Recently read an article that said for those who've been active cardiovascularly for years don't usually experience the usual drop of one BPM per year of life. How much of this is bunk, I don't know but do believe that as you're not experiencing pain/breathlessness you are good to go.