David, glad to see you are making good progress running. I recently started running as well, and i would like to know if you are using a heart rate monitor. I have debated the good and bad of cardio for a while. Coming from the Paleo community many focus on intervals and intensity, yet people forget that even “reformed chronic cardio’er” Mark Sisson recommends low level aerobic work. From what i can read, that means finding the right heart rate, and most of what i read comes back to the Maffeton Method which is 180-age and then subtract ten. For example, I’m 40 so my target heart rate range is 180-40 = 140 (top end) and minus 10 = 130 (bottom end). When i run i keep my heart rate at 130-140. For most people this seems VERY slow. I have to jog at a snail’s pace and walk some to keep my heart rate this low and I thought I was in “good” shape; however, by keeping out of the anaerobic range you don’t wear your body down and as you progress aerobically, you are able to run faster and faster at the same heart rate. The key is that running too hard (too anaerobic) is stressful (most on this forum are trying to decress stress) and the only way to know if you are working out too hard is to check heart rate. Staying in the pure aerobic range reduces stress and increases energy. Some believe it helps increase mitochondrial energy by helping them burn more oxygen ( similar to what Danny Roddy is trying to do by eating sugar). Just two weeks of training aerobically has boosted my energy levels. Let’s see where i am in 3-6 months.
I’m not saying anaerobic training is bad, just that its powerful medicine and until you have a very strong aerobic base you don’t want to add anaerobic training. Also, you can overtrain aerobically if you do no weight training and no anaerobic work. It’s about balance, but most of us are out of balance (too stressed) and aerobic training can help.