AS a normal person, you would like to live a long, long time. But how long can you expect to live? What is the limit of human life? Can you do something to prolong your life? What is the secret of longevity? These are good questions, and finding the answers to them could help you live much longer than seems possible today.
Before looking for these answers, we need to clarify the difference between two important expressions: “shelf life” and “life expectancy”. Life span refers to the biological limit of life span. Life expectancy refers to the average number of years a group of people born at the same time is expected to live. Unfortunately, throughout history, the life expectancy of man has been much less than the length of his life.
Life expectancy at various times
“In the length of a man’s days he can see and suffer many things that greatly displease him. For I have set the limit of man’s life at seventy years.” These were the words of Solon, an Athenian statesman and Greek lawgiver who lived around 600 BC. C. Thus, according to him, the duration of life was 70 years. However, according to the data of funerary inscriptions, around 400 a. C. life expectancy in Greece was approximately 29 years.
In ancient times, life expectancy in several European countries apparently did not vary substantially from that of ancient Greece. Due to the high mortality rate at a young age, the average life expectancy was much less than the length of life. The box on the next page gives the median age at death in selected European countries, providing a comparison of seniority with life expectancy around 1900 and today.
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 more than 73 years today, an increase of more than 25 years… Yet a critical look at these data shows that the increase in life expectancy results from the elimination of premature death and not from the extension of natural life.When life expectancy is calculated from particular ages, the higher the age, the smaller the increase. From the age of 40, life expectancy has increased relatively little. From the age of 75, the increase is barely perceptible. Beyond the age of 85, no increase at all can be determined with certainty… The best projections we can develop indicate that the median natural human lifespan is set at a maximum of 85 years.”
But what about the possibility of significantly prolonging the length of life through diet, vitamins, drugs, etc.? On page 18 of their paper, Fries and Crapo explain:
“For hundreds of years, alchemists have tried to prepare rejuvenating elixirs, without success. Literally hundreds of substances, including herbs, medicines, vitamins, animal cell extracts, fermented milk, and various serums and potions, have been reported to have rejuvenating properties, without convincing evidence. In our own country, traditional snake oil potions have fallen into disrepute, but we still have our vitamins. Recently, the drug gerovital has been promoted by Aslan in Romania as an agent to prevent aging. Gerovital, whose main ingredient is the local anesthetic Novocaine, it has been used in the treatment of Khrushchev [1894-1971]Sukarno [1901-1970]Ho Chi Minh City [1890-1969], and other dignitaries. Of course, there is no evidence that this agent has such effects, and there is no a priori reason to suppose that it should. The people cited as examples of high-profile users by gerovital advocates have died, and at normal ages.
“In 1974, Packer and Smith published an article in a prestigious American scientific journal reporting experiments that seemed to show that vitamin E markedly prolonged the lifespan of normal human fibroblast cells grown in a laboratory flask. retracted this claim, when neither they nor others were able to reproduce the experimental results. To date, no diet, lifestyle, vitamins, drugs, or tonics have been shown to prolong human life. Of the 4 billion human beings who have lived and died, almost all possible must have existed a combination of diet, chemical exposure and psychological life The absence of supercentenarians makes a strong argument that there is no easy path to a long life, or someone already I would have found it.”
Clearly, humans have not been able to extend their lives, though particularly by reducing the number of deaths from childhood diseases, life expectancy has been extended somewhat. From the human point of view, the hope of prolonging life span is indeed dim. However, there is a certain hope that human life will be extended. By what means?