MODULE SUPPLEMENT: MUSCULO-SKELETAL SYSTEM
What Are The Physiologic Processes That Cause These Changes?

Although more research is needed, there are changes that occur in several physiologic processes that appear to contribute to the changes seen in nerve and muscle tissue (Carmeli et al., 2002). Several of these were discussed in the sections on Theories of Aging: Free Radicals, Glycosylation of Proteins (The Maillard Theory), and Mitochondrial DNA Mutations (Note: The links above will open in new browser windows), each of which can lead to decreases in the synthesis of enzymes, proteins, and cellular energy stores.

Other factors that can contribute to or exacerbate muscle changes with age include malnutrition; a sedentary lifestyle or immobilization, both of which lead to deconditioning; altered hormonal inputs, such as decreased estrogen, testosterone, and growth hormone; and changes in the blood supply (Carmeli et al., 2002; Loeser & Delbono, 1999; Taffee & Marcus, 2000). Some of these are more amenable to interventions than others.