So what is an easy heart rate?

Early-ish start for my Morning run, was able to do 5 and half mile in 52 minutes, not the fastest of paces but I was running with my Heart Rate Monitor set to start bleeping at me at 150 Beats per minute which is a very easy pace, for me anyway. A lot of places give the following advice for heart rates

Maximum Heart Rate is 220 - Your age, so in my case 185

Fat burning 60 - 70 %, in may case 111 to 130
Aerobic 70 -80 %, for me 130 - 148
Anaerobic 80 - 90 %, for me 148 - 166

Well for me personally this does not stack up. I trotted around today whereas I ws supposed to be in the Anaerobic zone and that I certainly wsn't in. I suppose as I cycle a bit (50+ miles a week) I have a higher Maximum Heart Rate which is throwing the figures out. Time for some more research.