If you want to read quite a few articles on using an HRM and training zones, try
this. Some of the articles do not fully agree with each other, but they still make good reading and lots of it.
Speedlever, thanks for the endorsement of Idaho. I live west of Boise where those who can are intent on covering every square inch of land with new houses. Things have changed here a lot in the last ten years. Thanks also for not mentioning a certain US Senator who got caught tapping his foot in a public restroom. Although many of us liked him earlier, we now think it is time for him to go, IMHO.