This is my first visit to this site after getting very tired of another site, so I am catching up on some discussions you folks may have already become tired of. I read on page 3 of this topic a statement by MothAudio that caught my attention and I might have a reasonable explanation (sorry I have to figure out the quote function):
“I found the HRM to be effective in providing instant feedback, instead of waiting for mile splits I could maintain the proper effort late in the race when I was inclined to slow down. Actually, I was a bit surprized by my HR dropping as I assumed that it would rise as the effort increased. Just the opposite. It would only take a 10 second PM dropoff for that to happen and the HRM was helpful in making sure I pushed the pace. “Cranking it up” late in the race isn’t an ez thing to do. I would be very happy to just maintain my goal pace.”
MothAudio, I was thinking that when you said your “effort increased” what was going on was that your body had begun to accumulate more lactate and you started to feel worse. Your body couldn’t keep up that pace due to the effects of lactate on your leg muscles and you were forced to run slower. This would translate into a lower HR even though you felt like you were working harder. The HRM allowed you figure out that you had to increase your effort even more to get back to the previous HR – which probably cause even more lactate to be produced.
I’m not weighing in on the issues discussed in this thread. Just wanted to comment on Moths observation – whether I’m right or not is up to someone else to figure out. Anyway, I am experimenting with HRMs also and have not decide how much I will let it dominate my training. Right now I’m a low 2:50s marathoner (age 43) trying to break that darn 2:50 barrier, but my love for x-c ski racing may prevent me from putting in enough running/year to reach that more elusive goal of sub 2:40.