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Abstract
The aging process
Although established at the beginning of this century, the specialty of geriatrics has only recently been given the funding and attention appropriate to a medical discipline describing approximately one-fourth of the surgical population (1) .
Despite great advances in medical therapeutics, nutrition, and concepts of fitness , a large percentage of aging population will continue to have chronic disease (2) . For administrative and epidemiologic purposes, it is customary to consider the geriatric era as beginning at 65 years of age. However, some specialized applications classify persons 65 to 74 years of age as “elderly,” those 75 to 84 years as “aged,” and those 85 years and older as “very old.” In the absence of disease, active “elderly” persons maintain adequate normal daily functioning without major changes in lifestyle and with only minor adjustment in the level of activity. As they become “aged,” however, limitations in musculoskeletal strength, coordination, and quickness compel them to modify their daily routines dramatically (3) .
Aging is a progressive, universally prevalent physiologic process that produces measurable changes in the structure and decremental alteration of the function of tissues and organs. Although the mechanism is not yet entirely understood at a cellular or biochemical level, decreased cellular energy production due to deterioration of the mitochondrial genome, especially in cardiac and neural tissues, may play a fundamental role in the age-related decline of organ system capacity (3) .
There are marked differences between individuals with regard to their maximal capacities at somatic maturity, this explains the well-known clinical phenomenon in which some elderly patients appear to be “physiologically young” whereas others of the same age seem much less robust because of lesser organ capacity (4) .