Effects of Aging on the Muscular System

Effects of Aging on the Muscular System

Muscle tissue is formed in the mesoderm layer of the embryo in response to signals provided by fibroblast growth factor, serum response factor, and calcium. When fibroblast growth factor is depleted, myoblasts stop dividing and secrete fibronectin onto their extra-cellular matrix. The myoblasts then align into the myotubules followed by actual cell fusion, which requires adequate calcium. By approximately age 25, the skeletal muscles have reached their maximum size. After infancy and during the toddler period, muscle tissue increases very slowly, peaking during adolescence. Muscle is constantly built up and broken down rather evenly until about age 30, when muscle breakdown increases. By age 40, adults begin to lose between 0.5% and 2% of their muscle every year, though regular exercise helps prevent this.

With aging, skeletal muscles become less elastic as fibrosis occurs, which restricts movement and circulation­. Tolerance for exercise decreases and overheating may become a problem as a result of exercise. The ability to recover from injuries to mus-cles decreases, limiting repair capabilities and causing scar tissue to form. There are also losses in agility. By the age of 50, skeletal muscles lose about 20% of their mass. By the age of 80, they lose about 50% of their mass. For the elderly, exercise should be regular but not extreme to avoid damage to muscles, tendons, ligaments, bones, and joints. The common prob-lems related to aging of the muscular system include general weakness, slower movements, stiffness, decreased handgrip strength, increased chance of los-ing ­balance, development of arthritis, and increased risk of injuries.