LONGEVITY AND LIFE EXPECTANCY

The increase in life expectancy at all ages during the last two centur ies is in need of a quantitative model capable of resuming the whole p rocess under a single concept and simple mathematics. The basic hypoth esis was that through improved hygiene, medicine, and life-style, the stumbling blocks to the full expression of longevity were progressivel y removed. The mathematics of learning processes was then applied to t he secular evolution of life expectancy at various ages. The hypothesi s proved very fertile. Logistic equations fit long strings of statisti cal data, covering the evolution of life expectancy at various ages, f or both sexes, and in many European nations for almost two centuries. These life expectancy increases seem to move progressively to a common asymptote of about 79 yeats for men and about 84 years for women. It is suggested that these values are taken as a definition of longevity, presumably explicitating a coding in DNA. The evolution of life expec tancy during the last couple of centuries appears to follow consistent paths precisely mapped with simple mathematics. This opens the way to more integrated and holistic theories. (C) 1997 Elsevier Science Inc.