This is why I stopped using technology on my rides. I was getting obsessed with the numbers and jealous when people were higher/lower/blah, blah, blah. And, I found I was constantly looking at my monitor, which was not good.
I didn't learn anything that I already knew. 1) My HR is always higher than others of the same weight/height/age, despite the fact I have been fit for 25 years 2) At my size, it is incredibly hard to burn calories. I have to work twice as hard or ride three times as long to burn the same number of calories as someone who is of average height and heavier. Even when I was 32, weighed 90 lbs. and was teaching 7 fitness classes a week, my average HR was high during a work out. Since I don't have any cardiac issues, I assume it's just the way my body works.
So, I figure when I am breathing heavy at the top of a 15% grade, that is my cue that I am working hard. I also use my average speed or time over routes that I do all of the time to judge how my fitness progresses over the season.