Like some others here, my heart rate runs much higher than others. I'm 53 with a resting heart rate in the low 50's. My Max HR presently is 194 which isn't anywhere close to the 167 based on the 220 minus 53 rule...... I set my target zones on my HR monitor at 140 and 170. I can ride all day in that range but I know I'm going to struggle if I try and ride too much above 170. I completed a time trail last night and my average heart rate was 175 over a 24 minute period which was about all I can do.
Interestingly my brother and I are 12 years apart (he is younger) and our heart rates pretty much mirror each other on rides. A lot of the other guys we ride with (in their 30's and early 40's) heart rates are much, much lower than ours. Must have a lot to do with the genes.