The most commented post here on Training4cyclists.com so far was my question: What is your lowest heart rate ever? Maximum heart rate is often calculated as 220 minus your age, but there is a standard deviation on about 10 which means that 95% of us would fit into a formula called: 220 minus age +/- 20 beats. Thus, as you’ve already experienced, this formula does not have any practical usability for a serious endurance athlete.
But back to the topic, what is your highest maximum heart rate ever?
I did a maximal stress test 3 years ago – at age 62 – & reached 214bpm with no ill effects. This was to clear me for scuba diving. I now cycle regularly – 100+ miles each week – with arrythmia & can’t average over 16mph though I raced regularly until I was 21 then stopped for 42 years! Methinks I’ve left it too long as I’m dropped on the hills by an 84 year old, though he did ride 3 tours of britain.