If you regularly exercise your max is probably higher than estimated.
I was under the impression that the maximum heart rate is something that can not be trained. This source suggests that if anything training regularly would lower a persons max heart rate.
I just think that either one is serious enough about trying to optimize ones training efficiency, at which point the formula wouldn’t be accurate enough for me. Or one takes a more causal approach at which point doing most runs at “conversational pace” is a good enough rule of thumb.
Watched Gattaca (1997) the other day and really enjoyed it. Sci-fi movie that imo aged quite well and i somehow hadn’t seen until now.