Endocrinology of aging

Abstract

Throughout adult life, all physiologic functions gradually decline. There is a diminished capacity for cellular protein synthesis, a decline in immune function, an increase in fat mass, a loss of muscle mass and strength, and a decrease in bone mineral density (BMD). Most elderly individuals die from the complications of atherosclerosis, cancer, or dementia. However, in an increasing number of the healthy elderly, loss of muscle strength is the limiting factor that determines their chances of living an independent life until death. Muscle weakness can be caused by aging of muscle fibers and their innervation, pain related to osteoarthritis, and chronic debilitating diseases. In addition, a sedentary lifestyle and decreased physical activity and disuse seem, to be very important determinants in this decline in muscle strength, because exercise training even at a very old age has been demonstrated to reverse significantly the decline in physical capacity. In other words, "use it or lose it;" activity is an extremely important treatment for aging. © 2005 Humana Press Inc.