Maybe this is an impossible question, but I'd like to hear some opinions.

I just bought a heart rate monitor, and used it for todays ride. According to the instruction my max heart rate is 210 - 1/2 age - ( 0.11 x personal weight +4) in my case 210 - 38/2 - (.11 x 188 +4) = 166. So depending on my fitness level I should be working under 166; 70-80% is about 120-125.

My average heart rate for my ride was in the 170s! (the monitor doesnt have average, but i was watching it and it never went below 160 and actually peaked at 183).

My ride is rolling hills for 10.5 miles. I had and average speed of 16.4 mph and rode for 38 minutes. I tried to keep my cadence up and averaged around 85. I was breathing hard, but not dying and could have road another 10 miles at this pace if the sun held up.

Does this make any sense? Do I push to hard? Is the heart rate monitor no good?

Comments please