I am a believer in the use of heart monitors for training, especially for older runners such as myself. Today was my first day back in the shoes since November and my trusty Polar was on my wrist. 2 miles, 21:16, starting HR 80, Ave HR 141, Max HR 152. My pace is incidental only for tracking my improvement. I was happy with that, especially my first run in a while. I would like to revive any interest in hear monitors for anyone who is interested. They are certainly growing in popularity not necessarily because they are a cool gadget (although that is a big part for me - I am a gadget freak) but because they provide very useful data to the user. Especially if the user is older. Here is a post I made on the forum last season in response to some discussion on HRM use. "I'm glad to see the HRM thing is taking hold not just here but in general. (Especially for some of us who are older.) It is tough at first to change the mindset from pace (per mile) to (heart) rate. Yesterday and today I did virtually identical 5-mile runs except that today I missed a turn and ran an extra block. The difference between the two runs was my approach. Yesterday I ran with my HR in the higher end of my aerobic range and, in the last mile, allowed it to climb just into my anaerobic range (exactly what happens when you push to the finish line of a race). Today I forced myself to keep my HR to the low side of my aerobic range throughout the entire run which meant, as I got to the end and was heating up, I had to slow down in order to keep my heart rate in that range. As I ran each, I had no concern about my pace. In fact I never know my total run time in any of my runs until I stop my HRM and it then flashes my total run time. My mind stays focused only on my heart's "tachometer." Anyway, the end result was yesterday's pace was a push and today's was a relaxed pace, a beautifully comfortable run that I totally enjoyed. [The difference was 42 sec/mile!] Relaxed, slow comfortable, conversational runs should be part of our training routines. I've been using these devices since they first appeared on the market and swear by their use. Keep in mind that our body core temperature is the primary control of our heart rate during runs. As we heat up, the HR will rise. It's all cause and effect: not enough water, body temp rises, HR rises; humidity is up there, body temp rises, HR rises; emerge from shade into bright sun, body temp rises, HR rises. And when it does you see it (or hear it if you have a beeper) immediately and can adjust tempo accordingly. Also, it will be obvious that the HR will be higher on hot days so, if your goal is to run in a particular range, adjust the pace accordingly--you will still be putting out the same effort." John Heart monitor training information: http://www.marathonguide.com/training/articles/HeartMonitorTraining.cfm