I have this dilemma, I have been using a heart rate monitor to help my training for the past few years (not training for racing, just to improve fitness level and riding comfort/distance). In the beginning I was using the HAC4 and currently am using the Garmin Edge 305. My question is that I seem to have the same results with both monitors (so I am thinking I should rule out the monitors as a possible fault, only changed monitors as I wanted different features one didn't offer over the other, i.e. rear wheel mount for trainer use), and I am wondering if it something congenital. When I ride my exertion level doesn't seem that high (I can carry on conversations and such without problem), but I am routinely running in the 165-185 bpm range. Yesterday, I went for a ride with moderate wind (6-9 mph) and about 60 degree temp for 32 miles. Before even stepping on the bike, I was registering 123 bpm, and during I was always in the 170-185 range (did a few moderate hills) while averaging about 17 mph. Today I was averaging about 16 mph with 57 degree temp and little to no wind (with a 15 lb pack as this is my commute day), and I was running about 163-175 bpm for the 9.5 miles to work. I routinely check my BP and it is within acceptable range as per my doctor (123/83) and the system usually measures my heart rate at about 90-99 bpm. I have slept with the the heart rate monitor on and the average was about 65 bpm (this is what I am basing my resting heart rate at). Is there anything I can do to lower my heart rate, as I don't want to overexert my heart and is this something that I should be worried about?? I can and have seen many times my heart rate in excess of 205 bpm. I am getting in to see the doctor, but wanted others opinions. I am 35, 195 lbs, and 6'0", so I am slightly overweight, but I am a stocky person that has alot of bulk and no history of heart disease within the family. Should I be worried????