What it means
Sarcopenia is the progressive loss of skeletal-muscle mass, strength and function with age. It has had its own diagnostic code since 2016. The EWGSOP2 definition (2019) starts with low strength (grip under 27 kg in men, 16 kg in women), confirms it with low muscle mass (DEXA appendicular lean mass under 7.0 kg/m² in men, 5.5 in women), and grades severity by physical performance (gait speed under 0.8 m/s).
The drivers are anabolic resistance (older muscle needs more protein and more stimulus to respond), inactivity, low protein intake, falling hormones, chronic inflammation and the loss of motor neurons.
Why it matters for longevity
Muscle is the body's largest glucose sink, its protein reserve for illness, and the thing that prevents falls. Sarcopenia predicts hospitalisation, fractures, loss of independence and mortality, and it interacts with insulin resistance and inflammaging in both directions. It is the condition most of the muscle-related advice in longevity is trying to prevent.
What the evidence says
The cohort data are consistent: low muscle mass and strength predict mortality in older adults (meta-analysis of 21 studies, hazard ratio around 1.6–2.0 for the lowest category). The intervention data are among the strongest in the field: Fiatarone 1994 (NEJM) gave 100 nursing-home residents aged 72–98 ten weeks of resistance training and found strength gains of over 100% and improved gait and stair-climbing.
Protein matters alongside training: the PROT-AGE consensus recommends 1.0–1.2 g/kg/day for healthy older adults and 1.2–1.5 g/kg for those with sarcopenia, with 25–40 g per meal to overcome anabolic resistance. Creatine adds about 1.4 kg of lean mass to training in older adults.
How to measure or use it
- Screen with grip strength and a five-times sit-to-stand (over 15 seconds is a flag); confirm with a DEXA appendicular lean-mass index.
- Prevention and reversal: progressive resistance training two to three times a week, 1.2–1.6 g/kg/day of protein spread over three to four meals, creatine, and enough sleep.
- Track DEXA lean mass and grip every three to six months; a lean-mass loss of more than 1 kg in six months without intent is the signal to act.
Related
- Muscle mass and ageing — the full article, with the numbers
- The lean-mass protocol — what a plan to rebuild muscle contains
- Hormones after 40 — the hormonal contribution
Frequently asked questions
At what age does sarcopenia start?
Muscle loss begins around 30 at 3–8% per decade; it accelerates after 60. Clinical sarcopenia is usually diagnosed after 65 but can appear earlier in the inactive.
Can sarcopenia be reversed?
Substantially, at any age: resistance training doubled strength in nonagenarians in the Fiatarone trial. Protein and creatine amplify the effect.
How much protein do older adults need?
1.2–1.6 g per kg of body weight per day, with 25–40 g per meal, to overcome anabolic resistance.
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