body mass. This contraction reflects atrophic developments of skeletal muscle, liver, kidney, spleen, skin, and bone (15:1-5). In addition to decreased strength, the various other associated physiological effects include the following: (1) decreased renal blood flow and diminished glomerular filtration rate; and (2) increased adiposity with concomitant adverse effects on blood pressure, glucose clearance, and plasma lipoprotein profiles (14:73-74).
Moreover, one of the most significant causes of morbidity and mortality among the elderly consists of osteoporotic fracture. While osteoporosis among men has received less attention than osteoporosis in women, the male disease is also an important public health problem (11:133-134). Murphy et al. (1993) estimates that the probability of a man experiencing a broken hip by age 85 year is nearly 5 percent. Further, the age-specific hip fracture incidence rates have more than doubled over the past several decades.
The peripheral muscle weakness often experienced by many older individuals only increases their risk for hip fracture. Not only does it contribute to gait disorders, the weakness has also been linked to recurrent falls and immobility (12:M26). In addition, among the elderly, muscle weakness can interfere with many of the common activities of daily living. Such persons may, for example, have difficulty rising from a low chair or a lavatory seat. These kinds of problems can make older persons frail, and ultimately increase their dependence on others.
Until recently, much of this physiologic alteration was thought to be irreversible. In the 1970s, however, scientific investigators observed that sedentary lifestyles tended to accelerate the aging process. Moreover, advances in genetic engineering have given rise innovative pharmacologic approaches to these problems. Considering the adverse health effects of the age-related physiologic declines, any mechanism ...