So got my Garmin Forerunner 305 last week and love it!
I have been on 8, 4, and 10 milers with it and here’s what I’ve found out so far. The basis of heart rate monitoring is that it is a much more accurate indicator of exactly how hard your body is working, as opposed to say pace. Some days a 8 minute pace feels effortless and other days you are struggling to keep up. So when you go out for an “easy” recovery run you might actually be working harder than you should be. Then, of course, you are not getting the intended benefit of that recovery run.
Another very cool thing is I am using the max heart rate alert feature to let me know during my run if I’m pushing too hard. The Garmin breaks heart rate into zones (60%-70% Max, 70%-80% Max, etc…). Yesterday during my 10 mile run I got into zone five (90% Max) around mile 5 (it was hot out). This was way too early in my run to be working this hard and without an alert I would have died out around miles 8 or 9. However, as soon as the alarm went off I slowed my pace a little and adjusted my breathing for about 2 minutes just to get my heart rate back to zone four. It felt great and rather than struggling my last few miles, I finished strong with my fastest miles of the run!
I am totally sold on the benefits of HR monitoring