Aging: damage accumulation versus increasing mortality rate

Abstract

If aging is understood as some process of damage accumulation, it does not necessarily lead to increasing mortality rates. Within the framework of a suggested generalization of the Strehler-Mildwan (1960) model, we show that even for models with monotonically increasing degradation, the mortality rate can still decrease. The de-cline in vitality and functions, as manifestation of aging, is modeled by the monotonically decreasing quality of life function. Using this function, the initial lifetime ran-dom variable with ultimately decreasing mortality rate is ‘weighted’ to result in a new random variable which is already characterized by the increasing rate.