Could be regarding the bones and qi. More aggressive bone breathing exercises tend to leave me feeling wired though.
Afa jing and vitality are concerned, I don’t really see any issues with my more modern way of approaching the issue. Ultimately, I view the older meditative explanations as a form of engineering.
They were trying to explain various poorly understood phenomena utilizing mechanics specific to more subtle energies. Only modern people completely sold on the cult of materialism seem to have some weird problem with it.
Living robustly versus living longer was a topic the ancients understood very well from what I’ve seen. Prevention was really important as once something bad happened few tools existed to remedy a problem.
Extending ultimate lifespan was just as difficult back then as it is now. But living well was always the primary goal.