The purpose of the study was to find out whether a link could be established between hypothetical biological repair mechanisms, their decay, and longevity. Human biological functions (biomarkers) can be classified accordingly as their generally linear age-related decline starts at birth or in adulthood ( approximately 1% per annum), or occurs at a rate of less than approximately 0.5% per annum Sums of exponentially declining functions representing the decline of repair mechanisms are fitted to the averages of each of the above groups. The time constants of the mechanisms are lowest for those ceasing normal function at the age of approximately 35-40 years, i.e., approximately at twice the maximal age at which puberty is reached. An extrapolation of the overall loss of the mechanisms, postulated to account for the declining biomarkers, is, at present, such as to reach zero in the twelfth decade of life.