When most people think of building muscle, they imagine aesthetics — larger biceps, broader shoulders, or six-pack abs.
But new insights from longevity expert Dr. Peter Attia suggest that the appearance of muscle matters far less than its performance.
In a discussion with respected neuroscientist and podcaster, Dr. Andrew Huberman, Attia broke down the data on muscle mass versus muscle strength. Comparing low muscle mass individuals to those with high muscle mass reveals a 3x hazard ratio — a 200% increase in all-cause mortality risk for the weaker group.
However, when researchers tease apart the data, strength emerges as the true hero. Low strength relative to high strength carries approximately a 3.5x hazard ratio, or a 250% greater risk of death.
“It’s probably less the muscle mass fully doing that, and it’s more the high association with strength,” Attia explained.
To put this into practice, Attia’s medical practice has developed a Strength Metrics Assessment (SMA) consisting of 11 difficult tests designed to evaluate functional capacity. These go far beyond the typical grip strength tests used in research studies. Examples include:
- Dead hang: How long can you hang from a bar using your body weight? Goal for a 40-year-old man: two minutes. For a 40-year-old woman: 90 seconds.
- Farmer carry: Can you walk for two minutes carrying half your body weight in each hand? For women, the target is 75% of body weight.
- Air squat (no wall): Can you hold a 90-degree squat position for two minutes?
Other metrics in development include vertical jump height and ground contact time when jumping off a box.
These movements serve as proxies for what Attia calls the “Centenarian Decathlete” — a person thriving in their marginal decade of life (ages 90-100). The message: strength isn’t about looking fit. It’s about being functionally capable of living independently until the very end of life.