:Reliability theory of aging and longevity

{{short description|Biophysics theory}}

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The reliability theory of aging is an attempt to apply the principles of reliability theory to create a mathematical model of senescence.{{cite journal |last1=Gavrilov |first1=Leonid A. |last2=Gavrilova |first2=Natalia S. |title=Chapter 1 - Reliability Theory of Aging and Longevity |journal=Handbook of the Biology of Aging (Sixth Edition) |series=Handbooks of Aging |date=1 January 2005 |pages=3–42 |url=https://www.sciencedirect.com/science/article/abs/pii/B9780120883875500042 |publisher=Academic Press|doi=10.1016/B978-012088387-5/50004-2 |isbn=978-0-12-088387-5 }} The theory was published in Russian by Leonid A. Gavrilov and Natalia S. Gavrilova as Biologiia prodolzhitelʹnosti zhizni in 1986, and in English translation as The Biology of Life Span: A Quantitative Approach in 1991.{{cite book|last1=Gavrilov |first1=Leonid A. |last2=Gavrilova |first2= Natalia S. |editor1-last=Skulachev |editor1-first=V.P. |editor1-link=Vladimir P. Skulachev |title=Биология продолжительности жизни: Количественные аспекты |year=1986 |trans-title=Biology of Life Span: A Quantitative Approach |url=https://books.google.com/books?id=zMY5AAAAIAAJ |language=ru |edition=1st |location=Moscow |publisher=Nauka |publication-date=1986 |pages=167}}{{cite book|last1=Gavrilov |first1=Leonid A. |last2=Gavrilova |first2= Natalia S. |editor1-last=Skulachev |editor1-first=V.P. |editor1-link=Vladimir P. Skulachev |title=Биология продолжительности жизни: Количественные аспекты |year=1991 |trans-title=Biology of Life Span: A Quantitative Approach |url=https://textarchive.ru/c-1387064-pall.html |language=ru |edition=2nd |location=Moscow |publisher=Nauka |publication-date=1991 |pages=280 |isbn=5-02-013445-7}}{{cite book|last1=Gavrilov |first1=Leonid A. |last2=Gavrilova |first2= Natalia S. |editor1-last=Skulachev |editor1-first=V.P. |editor1-link=Vladimir P. Skulachev |title=Biology of Life Span: A Quantitative Approach |date=7 March 1991 |language=en |edition=1st |location=New York |publisher=Chur |publication-date=1991 |pages=385 |isbn=978-3718649839}}{{cite journal|author=A.J.S. Rayl |date=2002-05-13 |title=Aging, in Theory: A Personal Pursuit. Do body system redundancies hold the key? |url=http://longevity-science.org/TheScientist.pdf |journal=The Scientist |volume=16 |issue=10 |pages=20 |doi= |pmc= |pmid=}}

One of the models suggested in the book is based on an analogy with the reliability theory. The underlying hypothesis is based on the previously suggested premise that humans are born in a highly defective state. This is then made worse by environmental and mutational damage; exceptionally high redundancy due to the extremely high number of low-reliable components (e.g.., cells) allows the organism to survive for a while.{{cite web|url=https://spectrum.ieee.org/engineering-and-aging-the-best-is-yet-to-be |title=Engineering and Aging: The Best Is Yet to Be |work=IEEE Spectrum |date=2004-09-01}}

The theory suggests an explanation of two aging phenomena for higher organisms: the Gompertz law of exponential increase in mortality rates with age and the "late-life mortality plateau" (mortality deceleration compared to the Gompertz law at higher ages).Gavrilov, Gavrilova (2001).

The book criticizes a number of hypotheses known at the time, discusses drawbacks of the hypotheses put forth by the authors themselves, and concludes that regardless of the suggested mathematical models, the underlying biological mechanisms remain unknown."Conclusion" section of the book{{cite journal|last1=Gavrilov |first1=Leonid A. |last2=Gavrilova |first2=Natalia S. |date=2001-12-21 |title=The reliability theory of aging and longevity |url= https://www.researchgate.net/publication/11613344 |journal=Journal of Theoretical Biology |volume=213 |issue=4 |pages=527–545 |doi=10.1006/jtbi.2001.2430 |pmid=11742523|bibcode=2001JThBi.213..527G |citeseerx=10.1.1.295.6141 }}