Aging. Programmed change

Is aging due to random change or to a developmental program? This fundamental question motivates much research in gerontology and focuses clinical geriatrics research in different directions, as well. If aging changes are random, the prevalence and natural history of disease in the elderly might be unpredictable. Alternatively, if a developmental program continues to operate in late life, physiologic changes could predispose to certain disease or influence therapy in predictable ways. This article argues that the physiology of aging does result from a genetic program that continues to operate in late life.