Muscle strength and longevity

— What the evidence shows

In the PURE study of 139,691 adults in 17 countries, each 5 kg lower grip strength was associated with 16% higher all-cause mortality over a median of four years (hazard ratio 1.16). The association was consistent across age and sex, and grip strength predicted all-cause death more strongly than systolic blood pressure.

A meta-analysis of 16 cohort studies found that muscle-strengthening activity was associated with 10–17% lower risk of all-cause mortality and several diseases. The association was J-shaped: the largest difference, about 10–20%, appeared at roughly 30–60 minutes per week, with no clear additional benefit beyond that in the pooled data.

Systematic reviews of strength measures also find higher mortality with lower strength in apparently healthy adults.

Strength is closely tied to physical function and independence in later life, which is part of the healthspan question rather than the lifespan question alone.

— Strength as a marker, strength as a behaviour

This page carries two separate research questions that are easy to blur together. One asks what a measured capacity predicts; the other asks what a reported behaviour is associated with. They draw on different measurements and support different conclusions.

— What we know

• Grip strength is a reliable, cheap and reproducible predictor of mortality risk in older populations.
• Muscle-strengthening activity is included in major physical activity guidelines on the basis of health outcomes, not lifespan alone.

— What remains uncertain

• Grip strength is partly a general marker of health, so it may signal risk rather than cause it. Illness that is already present but undiagnosed can lower strength before death (reverse causation).
• Grip strength is measured with a dynamometer, while muscle-strengthening activity is usually self-reported; the two are different exposures and their findings should not be merged.
• Absolute strength differs by sex, body size and age, so a single threshold does not apply to everyone.
• The strength literature is smaller and more heterogeneous than the aerobic activity literature, and relies on varied self-reported measures.
• No trial has shown that resistance training extends human lifespan.

Sources

• García-Hermoso et al., Muscular strength as a predictor of all-cause mortality, Archives of Physical Medicine and Rehabilitation (2018)
• Momma et al., Muscle-strengthening activities and risk of mortality and disease, BJSM (2022)
• Leong et al., Prognostic value of grip strength: findings from the PURE study, The Lancet (2015)

Continue exploring

• Cardiorespiratory fitnessThe larger measured-capacity literature next door to this one.
• Physical activityThe aerobic behaviour evidence, and how it is measured.
• What affects longevityAll six factors, and the kinds of evidence behind each one.
• Healthspan by countryYears expected in good health, which is where function matters most.