5/8 — BUT ONLY TWO SIGNALS ACTUALLY BUILD BONE
This is where most people go wrong.
Heavy loading — weights genuinely hard enough that the last reps are a struggle, around 5-6 reps near failure.
Impact — jumping, hopping, heel drops.
That's it. Those are the stimuli bone responds to.
Walking, cycling, swimming, yoga, Pilates, and light weights are all excellent for other reasons — cardiovascular health, mobility, balance, longevity. They will not build density the way heavy progressive resistance and impact will.
Most women over 50 have been told to walk more and take calcium. That advice is not wrong. It is simply not sufficient, and it has cost an enormous number of people their independence.