I totally agree that physical abuse (over-use, that is) of one's body is not the way gracefully age. On the other hand NOT challenging
skeletal muscle to maintain (and even improve) is a sure way to lessen the quality of our years on this orb.
What might be effectively "heavy" in exercise is relative to who we have allowed ourselves to become. Wherever we are, however, improvements can be plotted, then achieved. Pick the right exercises, apply the proper loads, adopt responsible form, and perform your workouts with reasonable frequency.