1. Definition of Sarcopenia
Sarcopenia is characterized by the progressive loss of skeletal muscle mass, strength, and function that typically occurs with advancing age. Unlike normal aging changes, sarcopenia involves a measurable decline in muscle tissue that affects physical performance and overall health. This condition is not merely about muscle size but also about how effectively muscles function in supporting movement, posture, metabolism, and balance.
Estimates suggest sarcopenia affects approximately 10-30% of individuals over the age of 65, with prevalence increasing to over 50% in those aged 80 and older. While it is common, sarcopenia is not an inevitable consequence of aging, as lifestyle factors significantly influence its onset and progression.
2. Causes of Muscle Loss
Muscle loss in sarcopenia develops gradually, often beginning in mid-adulthood and accelerating after age 60. Several interconnected factors contribute to this decline:
- Hormonal changes: Reduction in anabolic hormones such as testosterone, growth hormone, and estrogen impairs muscle protein synthesis and repair mechanisms.
- Decreased physical activity: Sedentary behavior signals the body to downregulate muscle maintenance, leading to increased muscle breakdown and reduced regeneration.
- Nutritional insufficiencies: Inadequate protein intake, poor digestion, and deficiencies in essential nutrients limit the substrates required for muscle repair.
- Chronic health conditions: Inflammatory diseases, insulin resistance, and conditions like diabetes accelerate muscle degradation through metabolic disruptions.
Importantly, many of these causes can be addressed through targeted lifestyle interventions aimed at preserving muscle mass and function.
