Originally Posted by terrymorse
It's really, really hard to average 86% over 2 hours.
I just got back from a two hour mountain bike ride where my average HR was 160. My max is 194. (86% would be 166, so I was running about 83%) I feel fine, and I'm not in particularly great shape right now.
Mountain biking seems to really get my heart rate up a lot more than road riding.
Az