Why does muscle mass tend to decrease with age?

The decline in skeletal muscle mass that occurs with aging, a condition known as sarcopenia, is a multifaceted process driven by several factors.12

• Disuse and Atrophy: A significant portion of muscle loss is attributed to physical inactivity and the resulting atrophy of muscle tissue rather than a primary loss of muscle fibers. Muscles that are not regularly challenged tend to waste through the shrinkage of individual fibers.134
• Endocrine Changes: Aging is associated with a gradual decrease in the secretion of growth hormone and lower serum concentrations of IGF-1. This hormonal shift is believed to contribute to the reduction of muscle mass and the concurrent increase in body fat.5
• Structural and Metabolic Alterations: Aging involves gradual structural changes in tissues, including a decline in the number of cells and alterations in their constitution. These changes are often accompanied by a decrease in overall metabolic activity.31

While these changes are a natural part of the aging process, maintaining physical activity, particularly strength training, is essential for preserving muscle function, balance, and overall health in older adults.674