I have a new toy to play with on my runs now. A friend of mine bought a new heart rate monitor on Cragslist so he gave me his slightly used one. Now I can monitor my heart rate as I exercise and try to hit the target zones optimal for training. Yesterday it was very icy out so I opted to hit the gym and give the new gadget a try. I did impromptu speedwork, with a mile of warmup, followed by 3 miles of 2 laps hard, 1 lap recovery, and then another mile cooldown. During the speedwork session I was well into the 80-100% max heart rate that is optimal for speed training. My average for the session was 155 bpm, and max was 188. The max is actually only 2 bpm less than my maximum heart rate which is determined solely by my age. While I was working hard, it was certainly not an all out effort, so I suspect that my max heart rate is actually a little higher than 190.
It was nice getting out of the cold as all of my runs this week have been in the snow, which is really pretty, but adds another element to the workout. My quads have been sore since Wednesday!