Aging: physiological aspects and clinical implications.

Aging is not a new phenomenon, yet the physiology of aging is little understood. Several theories have been formulated to explain the aging process, ranging from immunological to free-radical theories of aging. Although the etiology of aging is important to understand, equally important is the differentiation of normal physiological changes from those associated with disease. The clinician's inability to recognize these differences may result in unnecessary testing, misdiagnoses and mismanagement of the elderly client. In addition, many of the changes associated with aging (e.g., decrease in visual acuity, impaired hearing) are potential hazards. One major role for the health care provider is to anticipate these changes, prepare the elderly client for them, and assist the elderly client in adapting to them. This article summarizes the physiological aspects of aging in the absence of disease and discusses some of the clinical implications related to these changes. Each system is addressed separately, as are the clinical implications related to that system.