If you try hard enough you can always find a plausible sounding excuse for failure. Discipline and good habits are the most effective way to prevent heart attacks in the first place. While there are a tiny fraction of people with serious mental health conditions or developmental disabilities which prevent them from making progress, that hardly applies to anyone on HN.
No one is arguing efficacy. We’re talking about how overly simplistic “just do it” is. Life isn’t a Nike commercial.