Sarcopenia is the loss of muscle mass that is associated with the aging process. The loss of muscle mass is, in part, responsible for the decline in the functioning of muscle as we get . This decline might be in its mechanical function (i.e., generating force, power, or braking movement) or in its roles a dynamic metabolic store, a generator of heat, or as a form of protective padding. In addition, the decline in mass also accounts for a significant proportion of the decline observed in maximal aerobic power with increasing age. As physical function declines with age, simple daily tasks such as rising from a chair unaided or climbing stairs become increasingly more difficult and, eventually, impossible to perform. This has important consequences for older people whose quality of life is reduced through a loss of independence and increased reliance upon others and also for the strain put upon health and social services charged with the care of an increasingly aging population. So why is muscle lost with increasing age? At the anatomical level it is clear that the loss of muscle is a reflection of a reduction in the number of muscle fibers and a reduction in the size of individual muscle fibers, notably the fast Type II fibers. However, although the aging muscle has lower rates of muscle protein synthesis (2,11), the mechanisms that may underlie this process of sarcopenia are unclear. This short review will focus upon a possible role for insulin-like growth factor (IGF-1) in sarcopenia.
Xanya Sofra Weiss
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