Definition and Diagnostic Criteria
Sarcopenia is the progressive loss of skeletal muscle mass and strength associated with aging. Diagnosis typically requires evidence of low muscle mass (measured by DXA or bioimpedance) combined with reduced grip strength or slow walking speed. It is now recognized as a distinct medical condition rather than an inevitable consequence of growing older.
Health Consequences
Sarcopenia significantly increases the risk of falls, fractures, and loss of independence. It is a major contributor to reduced healthy life expectancy and is associated with higher mortality rates even after adjusting for other health conditions.
The condition also impairs metabolic health by reducing the body's capacity to regulate blood sugar, since skeletal muscle is the primary site of glucose disposal. This creates a vicious cycle with metabolic syndrome.
Global Prevalence and Age Patterns
Prevalence ranges from 10% to 27% among adults over 60, depending on the diagnostic criteria and population studied. Muscle mass begins declining around age 30 at roughly 3-8% per decade, accelerating after 60. Ethnic differences in baseline muscle mass mean that universal cutoff values may not apply equally across populations.
Prevention Through Resistance Training
Resistance exercise is the most effective intervention for preventing and reversing sarcopenia. Combined with adequate protein intake (1.2-1.6 g/kg body weight daily), it can maintain or rebuild muscle mass at any age. Tracking physical performance metrics over time provides a practical way to monitor whether you are maintaining muscle function relative to your age group.