I don't know if it is because my heart rate climbs easy or what, but I'm really trying to build my aerobic base (as you have advised), and I'm running miles in like 9:30/mile pace. I am sticking to the 145-150 heart rate, because you strongly advised. I feel like I'm trotting. I usually have done my "easy" miles at like 7:30 pace, and that is too fast according to the heart rate. My PR's are 17:26/5k, and 36:32/10k. My max heart rate is over 200. Let me know if I should be going faster, or can go faster? I'm really excited to try this aerobic buildup, but I just feel like I'm getting nothing out of the run.