I did two events recently, a 5K and a trail half marathon. I have a Suunto watch with a heartrate strap, and from what I can tell it seems to be pretty accurate. I took the 20 minute test at the end of September and my average heart rate was 186 bpm. During the 5k at the end of November which I did in a little under 22 minutes (a little longer then the 20 minute test), my average heart rate was 1…