Originally Posted by dukeman

I think the key to using an HRM is to determine your max and also a baseline. I tend not to use it for my speedwork, but instead prefer to pay closer attention on the long runs and when racing. Typically during a long run I will try to keep it as low as possible (in the 150's), but after 2 hours it tends to creep up into the 160's. When racing (especially during a marathon) I tend to start higher and need to use the HRM to adjust my pace to get into my comfort zone (160's). If I start to hard in the 170's I don't seem to finish well. HRM's can be great tools, but I think some people rely much to heavily on them. I just don't take all of my workouts that seriously. I'm sure others have other opinions.