Grip strength is the most consistent predictor of all-cause mortality in middle-aged adults across multiple large studies. Stronger grip → longer life.
This is almost certainly not causal in itself — grip strength is a proxy for overall muscle mass, neuromuscular function, and the absence of wasting diseases. But as a proxy it's remarkably clean and easy to measure.
The practical implication: maintain and train grip strength. Deadlifts, farmer carries, hanging. It's both a training target and a biomarker worth tracking over decades.
Related: progressive-overload, sleep-and-performance