Sarcopenia is a progressive, age-related condition marked by the loss of skeletal muscle mass, strength, and physical performance, predominantly affecting individuals over the age of 65.

This muscle degeneration contributes significantly to frailty, increased risk of falls, fractures, disability, and mortality among the elderly population.

The term "sarcopenia" comes from the roots "sarx" meaning flesh and "penia" meaning loss, emphasizing its core feature—loss of muscle mass.

Pathophysiology and Causes

The development of sarcopenia is multifactorial. Natural aging processes reduce muscle fiber size and number, especially impacting type II (fast-twitch) fibers responsible for power and rapid movements, while type I fibers are less affected. Muscle tissue is gradually replaced by fibrous tissue, coupled with metabolic changes and oxidative stress.

Hormonal alterations involving testosterone, growth hormone, and insulin-like growth factor (IGF-1) further exacerbate muscle atrophy. Physical inactivity and inadequate nutrition, especially protein deficiency, compound these effects, accelerating muscle loss.

In some cases, sarcopenia may be complicated by "sarcopenic obesity," where muscle mass declines despite normal or elevated fatty mass, increasing health risks beyond those associated with obesity or sarcopenia alone.

Clinical Manifestations

Signs of sarcopenia include muscle weakness, slow walking speed, difficulty rising from chairs, decreased endurance, and weight loss related to diminished muscle bulk. Reduced muscle functionality compromises balance and mobility, heightening susceptibility to falls and fractures. Often, these symptoms may be subtle initially but progressively worsen, negatively impacting independence and quality of life in seniors.

Diagnosis and Evaluation

Assessing sarcopenia involves measuring muscle strength, quantity, and physical performance. Grip strength tests and chair-stand tests evaluate muscle function, while gait speed serves as a practical screening tool.

Imaging techniques such as dual-energy X-ray absorptiometry (DEXA), computed tomography (CT), or magnetic resonance imaging (MRI) quantify muscle mass. Bioelectrical impedance analysis (BIA) offers a less precise alternative. Diagnosis relies on established thresholds deviating markedly from healthy young adult reference values.

Management Approaches

Effective management integrates resistance exercise targeting muscle strength and balance, combined with nutritional interventions emphasizing increased protein intake and overall caloric adequacy. Physical activity remains the cornerstone to slow sarcopenic progression and improve outcomes. Additionally, addressing contributing factors such as chronic diseases and hormonal imbalances supports comprehensive care.

Dr. John E. Morley, a renowned geriatrician and expert in muscle aging and frailty, emphasizes, "Sarcopenia fundamentally threatens an elder's autonomy; combating it requires prioritizing muscle health through both lifestyle modifications and medical oversight."

Dr. Nancy E. Lane, a leading rheumatologist and musculoskeletal aging specialist, emphasizes, "Timely recognition and intervention in sarcopenia can dramatically reduce its debilitating effects and foster healthier aging trajectories."

Sarcopenia is a prevalent and debilitating syndrome characterized by progressive loss of skeletal muscle mass and function in older adults, leading to impaired mobility, heightened risk of falls, and reduced quality of life. Its pathogenesis involves complex biological, hormonal, and lifestyle factors that collectively reduce muscle integrity.

Comprehensive evaluation includes functional tests and imaging to confirm diagnosis. Management centers on resistance exercise and nutritional optimization to preserve muscle mass and strength. Expert consensus advocates early detection and multifaceted intervention to mitigate sarcopenia's impact on the aging population.