Ask a runner if a heart rate monitor is important and you'll get one of two answers. Either a hearty "Yes!" with an explanation of the merits of heart rate training, or else a resounding "No!" with why using a heart rate monitor is a big waste of time. Since yesterday was a rest day, I thought I would spend today discussing why I'm in the camp with the "Yes" men.
Before using an HRM, I ran every training run like it was a race. My PRs plateaued and I wasn't getting any better. It took Advanced Marathoning by Pete Pfitzinger to connect the dots.
My introduction to a heart rate monitor occurred about three years ago. At the time, my daughter and youngest son were pretty serious about rowing. They were going to a local rowing gym run by Olympic Gold Medalist Xeno Muller. One of Xeno's motivating speeches is the importance of aerobic conditioning. He credits his conditioning for his Gold Medal in 1996 and Silver Medal (despite having a chest cold) in the 2000 Olympics. Part of my kids training involved understanding this concept. They were required to use a heart rate monitor. Every few weeks, Xeno would perform a blood lactate test on them. After a good warm up, a blood sample would be taken and a testing device used to measure lactate concentration. Then, the intensity of the workout would be increased and another sample taken. This would be repeated for about 30 minutes. Xeno would then construct a graph of heart rate vesus lactate concentration. The point where the curve took off provided visual feedbck to the rower about the heart rate where lactate treshold occurred. Then, to aerobically train, the rower simply rowed or ran or cycled for hours on end just below (10 beats lower) that rate. Train harder and lactate would build at a rate faster than the body would flush it - reducing the effectiveness of each workout and leading to more time required for recovery, essentially taking time away from the time that *should* be used to build an aerobic base.
The same philosophy holds for running. The key to any good training plan are the hours and miles we put in at intensities below lactate threshold to build aerobic conditioning. Now - do we need a heart rate monitor to do that? Nope. Not at all. Running slow can be completely done by feel or by pace. But, the reason that Xeno used an HRM was to concentrate on heart rate instead of pace to measure a workout's effectiveness. He was a huge proponent that this was a more accurate measure to use when conditioning.
Now - back to the original question - why do I use a HRM? Well, I've bought into Xeno's philosophy. My daughter ended up with a scholarship. My son was racing internationally in the single scull by the time he was 16. It obviously worked for them. I use my heart rate monitor to make sure that I am not training too hard when I shouldn't be or not training hard enough when I should be. In theory, it keeps me out of lactate threshold when I shouldn't be there, and gets me there when I should be. If I ran purely by pace, I would have run too hard on Wednesday. My recovery run wouldn't have been a recovery run, but another lactate threshold run.
Should you use an HRM? If you are the type of person who would be bugged because the HRM is telling you to slow down, then it's probably not for you. If you want to (and can) run every hard workout BTTW, then it's not for you. But, if you are the type of runner who is frustrated because your PRs have seemed to plateau, or you can't seem to shake the injury bug, or you are frustrated that you just can't seem to get over that hurdle from 10K to Half or Half to Full, then maybe the problem is your aerobic conditioning. A HRM may help you stay out of lactate threshold and spend more time in your ideal aerobic zone. One thing for sure - it will make you understand that patience is a virtue.
In closing I can tell you this - using an HRM is not going give me the athletic talent to run a sub 4 marathon. But, I can't help but think that using my HRM has helped me get into better shape and has kept me from being injured. It has definitely kept me from turning every training run into a race. It's the reason that I am starting to worry about finding the *time* train these days.