Why is grip strength considered a longevity biomarker?

A BMJ meta-analysis of 42 cohort studies (DOI: 10.1136/bmj.k1651) found that each 5 kg reduction in grip strength was associated with 17% higher cardiovascular mortality and 9% higher all-cause mortality in men, making grip strength a more powerful mortality predictor than blood pressure in several large studies, and the minimum effective resistance training dose for longevity benefit is 2 sessions per week, with 3 sessions providing incrementally greater mortality risk reduction (Leong et al., Lancet, 201562000-6)).

Grip strength is not causative of longevity, it is a biomarker of musculoskeletal reserve, neuromuscular function, and the integrated physiological decline that occurs with aging. A man with strong grip strength also tends to have greater muscle mass, better insulin sensitivity, lower visceral fat, better balance, and more robust cardiovascular reserve, these all co-vary. The clinical utility of grip strength is that it condenses this complex of healthy physiology into a single measurable number achievable with a $30 dynamometer. It is the most powerful, cheapest, most practical longevity biomarker a physician can measure in a clinic.

Honesty Scale: Solid (1) for grip strength as a mortality predictor in large cohort meta-analyses.

What to do: Measure your grip strength with a calibrated dynamometer (available for $30–$60). For men, the reference ranges by decade: 40s, above 45 kg is good, 40–45 kg is average, below 40 kg is low; 50s, above 40 kg is good, 35–40 kg average, below 35 kg low. Test both hands, average 3 attempts each. Track annually.

For the full picture, read The Strength/Grip Deep Dive