Well after many years of running & biking I just realized that I've been exceeding my maximum heartrate. According to the formula my maximum heart rate should be somewhere around 167 BPM. After my last hard 5K run I did a quick unofficial check and it was at least 180 BPM.
I've been doing some research and found that if you want to optimize your workouts your should not exceed your MHR. So I just picked up a Sigma Sport PC 15 heart rate monitor on Ebay for $46.00. I can't wait to try it out. It cam be used for all sport and traing not only running & biking.
Does anyone else use a heart rate monitor?