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Unformatted text preview: Age-Related Physiological Changes and Their Clinical Significance GERRY R. BOSS, MD, and J. EDWIN SEEGMILLER, MD, La Jolla, California Physiological changes occur with aging in all organ systems. The cardiac output decreases, bloodpressure increasesandarteriosclerosisdevelops. The lungs show impaired gas exchange, a decrease in vitalcapacity and slower expiratory flow rates. The creatinine clearance decreases with age although the serum creatinine levelremains relatively constant due to a proportionate age-related decrease in creatinine production. Functional'changes, largely related to altered motility patterns, occur in the gastrointestinal system with senescence, and atrophic gastritisand altered hepatic drug metabolism are common in the elderly. Progressive elevation of blood glucose occurs with age on a multifactorialbasisand osteoporosis is frequently seen due 'to a linear decline in bone mass after the fourth decade. The epidermis of the skin atrophies with age anddue to changes incollagenandelastintheskinlosesits tone and elasticity.Lean body mass declineswith ag'e andthisis primarily due to loss and atrophy of muscle cells. Degenerative changes occur in many jointsandthis,combinedwiththelossofmuscle mass, inhibitselderlypatients locomotion. These changes with age have importantpracticalimplicationsfor the clinical management of elderly patients: metabolism isaltered, changes in response to commonly used drugs make differentdrug dosages necessary and there isneed forrationalpreventiveprograms ofdietand exercise in an effort to delay or reverse some ofthese changes. NORMAL AGING affectsall physiologicalprocesses. Subtle irreversiblechangesinthefunctionofmost organs can be shown to occur by the third and fourth decades oflife,with progressive deteriora- Referto: Boss GR, Seegmiller JE: Age-related physiological changes and their clinical significance, In Geriatric Medicine. West J Med 135:434-440, Dec 1981 Dr. Boss is Assistant Professor of Medicine, Division of Gen- eral Internal Medicine, Department of Medicine, and Dr. Seeg- miller is Professor of Medicine and Chief, Arthritis Division, De- partment of Medicine, University of California, San Diego, School of Medicine, La Jolla, California. Reprint requests to: Gerry R. Boss, MD, Department of Medi- cine, University Hospital, 225 Dickinson Street, San Diego, CA 92103. tionwith age.The rapidityofthedeclineinfunc- tion varies with the organ system under consid- eration but is relatively constant within a given system. Thus, the rateof aging isthe same for a 45-year-old man as itisforan 85-year-oldman; thedifferenceisthatby 85 yearsofagemore age- related changes have accumulated. An important concept not widely appreciated isthe distinction that must be made between the normal attrition offunction occurringinallpersonswithadvancing age and thelossoffunction thatmarks the onset 434 DECEMBER 1981 * 135 * 6 of pathologicalchanges from one or more of the diseases encountered withincreased prevalencein...
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This note was uploaded on 02/17/2011 for the course HK 490 taught by Professor Reidtky during the Fall '10 term at Purdue University-West Lafayette.
- Fall '10