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Free-Radical Theory of Aging

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The free-radical theory of aging was formally proposed by Denham Harman in 1956 and postulates that the inborn process of aging is caused by cumulative oxidative damage to cells by free radicals produced during aerobic respiration. Free radicals are atoms or molecules with single unpaired electrons. They are unstable and highly reactive, as they attack nearby molecules in order to steal their electrons and gain stability, causing radical chain reactions to occur. Free radicals are generated in vivo primarily within mitochondria during mitochondrial electron transport as well as by other physiological processes. Harman later extended the free-radical theory of aging to incorporate the role of mitochondria in the generation of free radicals and other reactive oxygen species. The theory proposes that the rate of oxidative damage to mitochondrial DNA primarily determines life span.

While free-radical reactions are implicated in the normal aging process, free-radical damage may...

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  • DOI: 10.1007/978-3-030-39903-0_191
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References and Readings

  • Beckman, K. B., & Ames, B. N. (1998). The free radical theory of aging matures. Physiological Reviews, 78, 547–581.

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  • Harman, D. (1956). Aging: A theory based on free radical and radiation chemistry. Journal of Gerontology, 2, 298–300.

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  • Harman, D. (1984). Free radical theory of aging: the “free radical” diseases. Age, 7, 111–131.

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  • Shringarpure, R., & Davies, K. J. A. (2009). Free radicals and oxidative stress in aging. In V. L. Bengtson, D. Gans, N. M. Putney, & M. Silverstein (Eds.), Handbook of theories of aging (pp. 229–243). New York: Springer Publishing Company.

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Correspondence to Carrie Brintz .

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Brintz, C. (2020). Free-Radical Theory of Aging. In: Gellman, M.D. (eds) Encyclopedia of Behavioral Medicine. Springer, Cham.

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  • Print ISBN: 978-3-030-39901-6

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