Longevity · Explainer
VO2 Max and Grip Strength: Two Numbers That Predict How You Age
Both are strongly associated with all-cause mortality. Both respond to training. Neither requires a lab to start improving.
By Julien Malet, · Updated 2026-09-07
Most longevity metrics are things you monitor. These two are things you can change, and the association with living longer and better is among the strongest in the literature.
VO2 max
VO2 max is the maximum rate at which your body can take in and use oxygen during intense exercise. It is the single best summary measure of cardiorespiratory fitness.
Why it matters: cardiorespiratory fitness shows a strong, graded inverse association with all-cause mortality across large cohort studies. In some analyses the difference in risk between the least fit and the most fit exceeds the differences attributable to smoking, diabetes or hypertension.
The most important detail: the curve is steepest at the bottom. Moving from the least-fit fifth of the population to the next fifth is associated with a larger risk reduction than moving from the second-fittest to the fittest. If you are unfit, the return on the first few months of training is enormous. If you are already fit, further gains matter less for mortality — which is good news for whoever is starting from nothing.
How to measure it. A proper test involves a mask, a treadmill and a lab, and costs $100–250. A smartwatch estimate is unreliable in absolute terms but reasonable at tracking your own direction over months, which is the part you can act on. A field test — a 12-minute run, or a 1-mile walk test — is free and fine for tracking.
How to improve it. The consensus structure is a base of easy aerobic work plus a small amount of hard interval work. Roughly 80% of your time at a conversational pace and 20% hard is a common prescription. Intervals of three to four minutes near maximum effort, repeated four times, are the classic VO2-max stimulus.
The dose that matters most is the one you will keep doing. A brisk 45-minute walk five times a week beats an interval plan you abandon in February.
Grip strength
Grip strength sounds trivial and is one of the better-validated predictors in the literature. Measured with a hand dynamometer, it is associated with all-cause mortality, cardiovascular mortality, disability and cognitive decline.
Why it predicts anything: grip is not important in itself. It is a cheap proxy for total-body strength, muscle mass and neuromuscular function — the things that determine whether you can get off the floor unaided at 80. It is a window into sarcopenia, the age-related loss of muscle that quietly decides how the last decades go.
How to measure it. A hand dynamometer costs $20–30. Squeeze maximally, three attempts per hand, record the best. Interpretation is by age and sex percentile; the useful comparison is your own number over time.
How to improve it. Not by training grip. Grip improves as a byproduct of getting stronger overall, so the intervention is resistance training — the major movement patterns, twice a week, progressively loaded. Deadlifts, rows, carries and hangs load grip incidentally, which is enough.
Protein supports the adaptation: around 1.6 g/kg, and creatine has real evidence for strength in older adults.
The overlap
These two measure different systems and point at the same intervention: move more, and lift something heavy twice a week.
That is unglamorous, free, and better supported than anything in a bottle. Which is the reason both sit near the top of the biomarkers worth tracking and near the top of our routine guide.
What to do this month
- Buy a $25 dynamometer. Record a baseline.
- Do a 12-minute run or 1-mile walk test. Record the distance or time.
- Start two resistance sessions and three easy aerobic sessions a week.
- Re-test both in twelve weeks.
If you are starting from a low base, the twelve-week change will be larger than anything else on this site can offer you.