Hi Mark and Luis,
One question: I've noticed that you position an interesting HR approach for training (180-age+5 in my case = 149) as maximum aerobic heart rate. Would that HR be the same for everybody with my age that practices 7+ times/week? I have a friend who trains for triathlons as well, but his max HR is 185, while mine is 207. Wouldn't our maximum aerobic heart rates be different as well?