Should You Lift Heavy For Bone Density?

If you've spent any time in fitness spaces, especially those targeting women and athletes over 40, you've heard it: lift heavy for bone density. It's presented as settled science, a non-negotiable recommendation, the thing standing between you and osteoporosis. Every fitness influencer, personal trainer, and wellness podcast seems to agree: heavy resistance training builds bone, and if you're not doing it, you're basically crumbling as we speak.