What is sarcopenia?
Sarcopenia is a progressive and generalized loss of skeletal muscle mass and strength that occurs with aging. The term comes from the Greek words for "flesh" and "deficiency". While some muscle decline is normal with age, sarcopenia is an accelerated loss that significantly impacts daily life. It can be primary, due to aging alone, or secondary, caused by factors like inactivity or chronic illness.
Symptoms and indicators of sarcopenia
Symptoms often develop gradually and may include loss of strength (making tasks difficult), slow walking speed, reduced stamina, balance problems, reduced muscle size, and difficulty with daily activities like rising from a chair.
The many causes of age-related muscle loss
Sarcopenia is caused by several factors, including the natural aging process, which accelerates muscle loss after age 60. Physical inactivity is a major contributor, as are hormonal changes like declining testosterone and IGF-1. Poor nutrition, particularly insufficient protein and vitamin D intake, also plays a role. Chronic diseases such as cancer, kidney disease, and diabetes increase risk, as can chronic inflammation and a decrease in nerve cells signaling muscles.
Diagnosing sarcopenia
Diagnosis involves assessing muscle strength, quantity, and physical performance. Tools used can include handgrip strength tests, Timed Up-and-Go tests, and imaging techniques like DXA or BIA to measure muscle mass. Diagnostic criteria have been established by groups like the EWGSOP.
The difference between sarcopenia and cachexia
Both involve muscle loss but differ in cause and characteristics.
| Feature | Sarcopenia | Cachexia |
|---|---|---|
| Primary Cause | Age-related, often compounded by inactivity, malnutrition, and hormones. | Systemic disease (e.g., cancer, COPD, HIV/AIDS) and inflammation. |
| Key Characteristic | Progressive loss of muscle mass, strength, and function. | Severe weight loss, including both muscle and fat mass, driven by inflammation. |
| Metabolic Changes | Imbalance between muscle protein synthesis and degradation. | Altered metabolism and increased protein breakdown due to systemic disease. |
| Effect on Appetite | Appetite is typically not a primary symptom. | Anorexia (loss of appetite) is a core indicator. |
| Treatment Focus | Exercise (especially resistance training) and nutritional strategies. | Treatment of the underlying disease, alongside nutritional support and exercise. |
Treating and managing sarcopenia
While not fully reversible, managing sarcopenia involves lifestyle changes to slow its progression.
Exercise interventions
Exercise is key, especially resistance training which builds muscle strength and mass.
- Resistance training: Includes weights, bands, or bodyweight exercises at least twice weekly.
- Aerobic exercise: Improves overall health and endurance.
- Balance training: Reduces fall risk.
- Consistency is key: Combined strength, aerobic, and balance programs are most effective.
Nutritional strategies
Diet is critical for muscle health and overcoming anabolic resistance in older adults.
- Increase protein intake: Aim for 1.2-1.5 g/kg body weight daily from sources like meat, fish, eggs, dairy, and legumes.
- Distribute protein intake: Eating protein throughout the day may boost muscle protein synthesis.
- Vitamin D: Important for muscle function; supplements may be needed.
- Omega-3 fatty acids: Found in fatty fish, they have anti-inflammatory benefits for muscles.
The long-term impact of sarcopenia
Unmanaged sarcopenia increases the risk of falls and fractures, leading to physical disability. It's also linked to higher healthcare costs, hospitalizations, and is an independent predictor of mortality.
Conclusion
Sarcopenia is a common and treatable condition, not an inevitable part of aging. Understanding its meaning and taking action through exercise, especially resistance training, and proper nutrition can slow its progress, maintain strength, and preserve independence. Consult a healthcare provider if you notice signs of decline. For more information, visit the National Institutes of Health website.
