Digibud, I think chinarider was making the point that you max HR isn't just a function of the efficiency of the heart muscle itself, but a product of general aerobic fitness- but I agree that for practical purposes it's probably academic.

I'm not persoanlly convinced, however, that one's HR is all that informative about one's fitness. Yes, resting HR is generally lower in the fit than in the unfit. But I have a cycling buddy, 12 years younger than me, whose resting HR is similar to mine but who rockets up into the 150s and 160s with effort. When we ride together he routinely averages 150+ while I'm averaging in the 130s, but he seems no more distressed than me and can still outsprint me at the end. He is a crappy climber though, if that means anything...