The Handshake Test: The Longevity Biomarker You Can Measure for $20
Grip strength predicted mortality better than blood pressure in a study of 139,000 adults across 17 countries. Here is how to measure yours, where your number falls, and what to do about it.
Most clinical visits end with a blood pressure reading. The research behind that number is solid: decades of trials, hundreds of thousands of participants, clear mechanistic links between cardiovascular risk and the reading from the cuff. Which makes what Darryl Leong and colleagues published in The Lancet in 2015 counterintuitive: a forearm squeeze predicted the risk of dying from any cause better than systolic blood pressure did.
The test takes less than two minutes and costs around $20. Almost no doctor currently uses it as a routine screening tool.
The Study Behind the Finding
Leong and colleagues analyzed data from the Prospective Urban Rural Epidemiology (PURE) study, a large longitudinal cohort spanning 17 countries across three continents, from high-income to low-income settings.¹ Of the 139,691 participants followed over a median of four years, each completed a grip strength assessment using a Jamar dynamometer (a clinical hand-squeeze device), recording the maximum force they could produce.
Pick up an 11-pound (5 kg) bag of potatoes at the supermarket and hold it at your side for a moment. That’s the unit the study measured by. The study found that a grip decline of just that amount was associated with a meaningfully higher risk of dying from any cause over the follow-up period. The comparison is what made the finding remarkable: grip strength predicted who would die sooner more reliably than blood pressure did. The measurement that has driven cardiovascular medicine for over a century, that determines prescriptions and referrals and lifestyle advice in clinics everywhere, was outperformed by a five-second hand squeeze.¹
A 2022 systematic review and dose-response meta-analysis confirmed this pattern across a far wider evidence base.² Pooling data from prospective cohort studies including over 1.8 million participants, it found that the relationship between higher grip strength and lower mortality risk follows a near-linear inverse pattern: gains in grip strength at almost any level are associated with lower risk, not just gains that bring someone above a clinical threshold.
Why a Forearm Squeeze Tells You This
Grip strength marks these outcomes rather than causing them. Understanding what it marks is what makes the finding clinically meaningful.
The biological requirements for a strong grip overlap substantially with those for cardiovascular and metabolic longevity. A functioning neuromuscular system and adequate protein synthesis are among the most important. When any of these systems begins to decline, grip strength tends to decline alongside them.
More specifically: grip is one of the most reliable proxies for total skeletal muscle mass. And skeletal muscle isn’t passive tissue. It secretes proteins called myokines (biological messengers released during muscle contraction) that regulate inflammation and improve insulin sensitivity (the body’s ability to use blood sugar effectively), among other functions. An adult with strong grip tends to have more metabolically active muscle, and that muscle is doing real biological work in ways that matter for longevity.
Where blood pressure reflects the state of one vascular system, grip strength reflects the state of several interconnected systems simultaneously. That’s likely why it outperformed blood pressure in a cohort of 139,000 adults followed across 17 countries over four years.
What This Means for You
Grip strength is one of the few longevity markers you can test and track at home, without a lab or a clinical appointment. The paid section covers how to measure it correctly with a ~$20 dynamometer, where your result places you relative to both clinical thresholds and age-matched norms for your decade, and the eight exercises with the strongest evidence for building grip and the muscles along the back of the body that grip relies on most. Your grip strength norms and training tracker comes with it, so the number you measure today becomes a baseline you can actually follow over time.
