Since my 40'ies, I've noticed that my max hr drops during the training season as I get fitter. I would also notice a dramatic drop in my aerobic limit hr (at same effort) during the same period. As I get older my max hr is dropping, which is to be expected, according to all literature around this....BUT The question that I have never really got an answer to is - why would my max hr drop significantly as I get fitter. This is supposed to be genetically fixed and most articles only point to slight changes when cross-training in other disciplines (Eg. running vs cycling) It is not a question of it just being easier because you are fitter either. After many years of cycling (age now 60), I know when the body is telling me when I'm working close to or at max. The other day I chased a youngster on a road bike, while I was on a MTB. Got to absolute max effort whilst doing >55kph on fairly level road. My max HR for this effort was given as 171bpm by my HRM. Earlier in the season I regularly saw 185bpm. This is a 15 beat drop!! Anybody that had the same experience or can point me to literature that clarifies this phenomena??
