The Secret of Longevity

As a normal person, you would like to live for a long, long time. But how long can you expect to live? What is the limit of the human life span? Can you do anything to extend your life span? What is the secret of longevity? These are good questions, and finding the answer to them might help you to live much longer than seems possible at present.

The alchemist

The alchemist, painting by Sir William Fettes Douglas (1822 - 1891).

As a normal person, you would like to live for a long, long time. But how long can you expect to live? What is the limit of the human life span? Can you do anything to extend your life span? What is the secret of longevity? These are good questions, and finding the answer to them might help you to live much longer than seems possible at present.

Before looking for these answers, we have to clarify the difference between two important expressions: “life span” and “life expectancy.” Life span refers to the biological limit to the length of life. Life expectancy refers to the average number of years that a group of people born at the same time might be expected to live. Sadly, throughout history man’s life expectancy has fallen far short of his life span.

Life Expectancy at Various Times

“In a man’s length of days he may see and suffer many things that he much dislikes. For I set the limit of man’s life at seventy years.” These were the words of Solon, an Athenian statesman and Greek lawmaker who lived about 600 B.C.E. Thus, according to him, the life span was 70 years. However, according to data from burial inscriptions, about 400 B.C.E. the life expectancy in Greece was approximately 29 years.

In ancient times, apparently the life expectancy in various countries of Europe did not vary substantially from that in ancient Greece. Because of the high death rate at an early age, the average life expectancy fell far short of the life span. The box on the next page gives the average age at death in some European countries, providing a comparison of that of ancient times with the life expectancy about the year 1900 and at the present time.

Regarding the increase in life expectancy, James F. Fries and Lawrence M. Crapo wrote in their work Vitality and Aging, 1981, pages 74-6:

“The average length of life in the United States has increased from approximately 47 years at the turn of the century to over 73 years today, an increase of more than 25 years. . . . A critical look at these data, however, shows that the increase in life expectancy results from the elimination of premature death rather than by extension of the natural life span. When life expectancy is calculated from particular ages, the higher the age, the less is the increase. From age 40, life expectancy has increased relatively little. From age 75, the increase is barely perceptible. Beyond the age of 85, an increase cannot be confidently determined at all. . . . The best projections we can develop indicate that the median natural human life span is set at a maximum of 85 years.”

But what about the possibility of extending the life span significantly by diet, vitamins, drugs, and so forth? On page 18 of their work, Fries and Crapo explain:

“For hundreds of years, alchemists attempted to prepare rejuvenating elixirs, without success. Literally hundreds of substances, including herbs, drugs, vitamins, extracts of animal cells, fermented milk, and various serums and potions have been reported to have rejuvenating properties, without convincing evidence. In our own country, the traditional snake oil potions have fallen into disrepute, but we do still have our vitamins. Recently, the drug gerovital has been promoted by Aslan in Rumania as an agent to prevent aging. Gerovital, whose main ingredient is the local anesthetic Novocaine, has been used in treatment of Khrushchev [1894-1971], Sukarno [1901-1970], Ho Chi Minh [1890-1969], and other dignitaries. There exists, of course, no evidence that this agent has any such effects, and there are no a priori reasons to assume that it should. The persons cited as examples of prominent users by gerovital proponents all died, and at unremarkable ages.

“In 1974, Packer and Smith published a paper in a prestigious American scientific journal reporting experiments that seemed to show that vitamin E markedly prolonged the life span of normal human fibroblast cells cultured in a laboratory flask. Later, they retracted this claim, when neither they nor others were able to reproduce the experimental results. To date, no diets, lifestyles, vitamins, drugs, or tonics have been shown to extend the human life span. Of the 4 billion human beings who have lived and died, nearly every possible combination of diet, chemical exposure, and psychological life must have existed. The absence of super-centenarians argues strongly that there is no easy track to long life, or someone would have found it by now.”

Clearly, humans have not been capable of extending their life span, although particularly by reducing the number of deaths from childhood diseases, life expectancy has been extended somewhat. From the human standpoint, the hope of extending the life span is dim indeed. However, there is a sure hope that the human life span will be extended. By what means?

Copyright © 2007 Lenith Hinaloc

Comments

Lenith Hinaloc is a bit too dogmatic. We do not know whether we are, or have been, capable of extending the human life span. For at least two good reasons:
1. We don't know what it actually is - except by projecting or accepting the data on the longest living humans. No one dies of old age, they die of particular causes - each of which are known to be avoidable. This projection rests on the data - change the data (as it is doing), and you change the (otherwise unknown) implied life span.
2. The life expectancy of all, and particularly the oldest, has been increasing in a linear fashion since records have been accurately and comprehensively kept. This implies there is no limit.

The plausible argument that there are no super-centenarians may be due to an inherent life span, but equally may not be - it could be that previous generations were more susceptible to the ravages of disease, accident, war, etc.