This paper introduces a frailty index as a method to assess health status in elderly individuals, defined as the proportion of accumulated deficits (symptoms, signs, functional impairments, and laboratory abnormalities). The index serves as an individual state variable reflecting the severity of illness and proximity to death. Using a representative database of elderly Canadians, the authors found that deficits accumulate at a rate of 3% per year and follow a gamma distribution, typical for systems with redundant components. The slope of the index is insensitive to the specific deficits, making it a robust prognostic factor for life expectancy. The paper also explores the statistical distribution of the frailty index, which is gamma-distributed for well groups and normal for morbid groups, reflecting the increase in uncompensated deficits in impaired organisms. The accumulation of deficits is proposed as a macroscopic variable that reflects general properties of aging at the whole-organism level, making it a potential proxy measure of aging. The authors conclude that the frailty index can be used to estimate survival probability and distinguish between successful aging and senescence, highlighting the importance of damage control and prevention mechanisms in aging.This paper introduces a frailty index as a method to assess health status in elderly individuals, defined as the proportion of accumulated deficits (symptoms, signs, functional impairments, and laboratory abnormalities). The index serves as an individual state variable reflecting the severity of illness and proximity to death. Using a representative database of elderly Canadians, the authors found that deficits accumulate at a rate of 3% per year and follow a gamma distribution, typical for systems with redundant components. The slope of the index is insensitive to the specific deficits, making it a robust prognostic factor for life expectancy. The paper also explores the statistical distribution of the frailty index, which is gamma-distributed for well groups and normal for morbid groups, reflecting the increase in uncompensated deficits in impaired organisms. The accumulation of deficits is proposed as a macroscopic variable that reflects general properties of aging at the whole-organism level, making it a potential proxy measure of aging. The authors conclude that the frailty index can be used to estimate survival probability and distinguish between successful aging and senescence, highlighting the importance of damage control and prevention mechanisms in aging.