Sarcopenia: Understanding Muscle Loss and Its Impact

Sarcopenia is the age-related loss of skeletal muscle mass, strength, and function. It begins ~age 30, accelerates after 60, and affects 10–20% of older adults.

Diagnostic Criteria (EWGSOP2)

1. Low muscle strength (grip strength <27 kg men, <16 kg women; or chair stand test >15 sec for 5 rises).
2. Low muscle quantity/quality (DXA, BIA, CT/MRI).
3. Low physical performance (gait speed <0.8 m/s, SPPB ≤8) = severe sarcopenia.

Causes & Risk Factors

• Primary: Aging (anabolic resistance, denervation, hormonal changes).
• Secondary: Physical inactivity, malnutrition (low protein/vitamin D), chronic diseases (heart failure, COPD, CKD, cancer), medications (corticosteroids), inflammation.

Consequences

• Frailty, falls, fractures, disability
• Loss of independence, hospitalization
• Metabolic dysregulation, insulin resistance
• Increased mortality
• Reduced quality of life

Management: Multimodal Approach

1. Resistance Exercise (Cornerstone)

• Progressive resistance training 2–3×/week.
• 8–12 reps × 2–3 sets at 70–80% 1RM.
• Focus on major muscle groups; include power training.

2. Nutrition

• Protein: 1.2–1.5 g/kg/day (evenly distributed; leucine-rich).
• Vitamin D: Supplement to >30 ng/mL.
• Calories: Adequate to prevent catabolism.
• Consider creatine, omega-3, HMB (evidence emerging).

3. Medical Optimization

• Treat underlying conditions.
• Review medications (minimize corticosteroids).
• Testosterone/HRT only if clinically deficient (controversial for sarcopenia alone).
• Novel agents (myostatin inhibitors, SARMs) under investigation.

Prevention Starts Early

Lifelong physical activity and adequate protein intake build "muscle reserve" to delay onset.