OUCH
Seriously, how did you feel at 220, light headed, dizzy, wanted t vomit, shaking, or did you have more?
Any age based formula is purely & simply a guideline.
I beleive that 220- age was based on a sample of sedentary individuals.
The factthat they were sedentary may or may not be relevant.
I still use age based formulae because I haven't done a stress test, but I've now changed 3 times after exceeding my theoretical age based MHR.
Stress test will be done sometime next year, not a lot of point at the end of September.