Is strength or muscle mass more important as you age?

Key numbers

How muscle and strength change with age

Muscle mass and strength can follow quite different paths as people get older. A 2012 review found that studies measuring both in the same people report strength falling two to five times faster than mass.

Longitudinal studies, which follow the same people over time, show that at age 75 women lose 0.64-0.70% of their muscle mass per year, while strength falls 2.5-3% per year in women and 3-4% per year in men.

Studies that compare younger and older people at a single point in time give smaller and much less consistent figures. The median rate of muscle loss they report is 0.47% per year in men and 0.37% per year in women, and estimates vary widely with the measuring technique and the group studied. None of these figures is a fixed rate that applies to everyone.

What a three-year study of older adults found

The Health, Aging and Body Composition Study measured muscle mass and strength in 1880 older adults over three years. Leg lean mass fell about 1% per year in that cohort. Leg strength fell about three times faster, at annual rates ranging from 2.6% in White women to 4.1% in Black men (3.4% in White men).

Both men and women lost strength, and men lost almost twice as much as women. In that cohort, maintaining or even gaining muscle mass did not prevent the decline in strength.

Why strength tracks wellbeing more closely, and why mass still matters

The 2012 review concluded that loss of strength is a more consistent risk factor for disability and death than loss of muscle mass, and that low strength is a more constant factor in poor wellbeing in old age. Those are associations in groups of people, not a measure of any one person's risk.

Muscle mass is still considered a major determinant of strength loss, and in the three-year study losing mass went along with losing strength. Strength falling faster than mass suggests that muscle quality, the force a muscle produces for its size, also declines with age. So both the size of a muscle and its quality deserve attention.

The evidence

Each cited source is labeled according to how it supports the particular claim on this page. Direct test evidence, underlying-capacity findings and population reference values are distinguished from Systematic-defined protocols and standards. Historical development notes are retained internally rather than presented as public evidence. A study of an underlying capacity is never presented as validation of the Systematic test itself.

• Normative/reference evidence New source

  Mitchell et al. (2012). Sarcopenia, dynapenia, and the impact of advancing age on human skeletal muscle size and strength; a quantitative review. Frontiers in physiology.

  What it found. Strength is lost more rapidly than muscle mass with age, and loss of strength is a more consistent risk factor for disability and death than loss of mass. Longitudinal and cross-sectional rates are reported separately, by sex.

  What it does not show. It does not show that muscle mass is unimportant, or that one yearly rate of loss applies to everyone.

  PubMed 22934016

• Underlying-capacity evidence New source

  Goodpaster et al. (2006). The loss of skeletal muscle strength, mass, and quality in older adults: the health, aging and body composition study. The journals of gerontology. Series A, Biological sciences and medical sciences.

  What it found. In 1880 older adults followed for three years, leg strength fell about three times faster than leg lean mass, and maintaining or gaining mass did not prevent the strength decline.

  What it does not show. It does not show that muscle quantity is unimportant, or that every older adult declines at the reported sex- and race-specific rates.

  PubMed 17077199