At 93, he's as fit as a 40-year-old. His body offers lessons on aging

Dupe: https://news.ycombinator.com/item?id=39019059

Frail and inactive. Correlation? Causality? Direction?

In a study, post-menopausal women weight-trained, giving 40% increase in bone density.

The inactivity of "retirement" kills. Use ^ lose.