As I mentioned in another thread (which I didn't want to derail) I mentioned that I'd recently done a ramp test to evaluate my FTP improvement. The graph of HR and power demonstrates why I don't use the 220-age formula. If I'd stopped at the 220-age predicted maximum heart rate that would have been 25 bpm below my actual observed maximum. More importantly, it would have been 130 watts below exhaustion, which is huge.
Obviously, if you have known or suspected heart issues, consult your doctor. But if you've been limiting your efforts to an age-based formula, you may be cheating yourself.