Bit of an old thread, and only just spotted this, but the 220 BPM minus your age to determine max HR is flawed and was recognised as such as soon as it came out but it was never challenged and remain to this day so do not even use it. If you read up on it, they carried out trials on another 43 methods all similar and concluded that no acceptable formula works, but it might for the odd individual person, just like astrology, 12 birth signs, a daily prediction for each what will happen that day, for some it comes true but for the majority it does not. How often does 1/12th of the World get rich in one day if that was the prediction. To show how innacurate it is, I am 62, therefore using the formula, my Max HR should be 158BPM, but it is way out, my max HR is 196. As my doctor says to me"You have a very unnatural healthy heart" and even the nurse who does my medicals can only accept the figures after I tell her that I do a lot of cycling and keep fit.