Are you wearing a chest strap or wrist HRM? The chest is very accurate, wrist-worn are not and tend to run higher than actual beats, especially in the upper ranges or when running (arm swing messes up the light that is reading the pulse off your skin--chest straps are a direct read off your heart). If a wrist monitor is worn, you are probably not working as hard as appears. So, either you are super fit and working too hard with a chest strap or not really as high as you think with a wrist-worn. The old 220 - age formula puts Max HRs too low for trained athletes. It was designed to allow achievable zones for average people. The 200 - age formula says my max is 161. I am almost 60 and race XC mountain bikes in Cat 2 aka Sport categories. Although I've hit 179 in races, I consider my max to be 177. I wear a chest strap that is sync'd to my Garmin 520 Plus. Here are my typical HRs so you can compare: Training rides--128 to 134 avg, 160 to 162 max; XC Races-- 160-164 avg, 172-177 max (and I'm in that avg for 93-96% of the 1-1.5 hour race!). Riding on own, no one can hit as high as being pushed in a race. I know everyone is different, but are you really riding at race pace every ride?