The maximum human lifespan is around 125 years. However, some experts believe that this limit could be extended by somewhere between 10 and 15 years.
So far, the oldest person whose age could be proved was a Frenchwoman who died in 1997 at 122 years of age. In 1933, The New York Times reported the death of a Chinese man who was allegedly 253 years old, but this and similar reports of people living to such great ages are now considered unreliable.
Over the course of history, there has been no change in the maximum age, which is the same for all ethnic groups. What has increased since the end of the 19th century is the average life expectancy in industrialised countries. Thanks to the improvement in living conditions, this is now between about 79 and 82 years for both sexes (at birth).
Why is it that women live longer than men?
On average, women live seven years longer than men, although in some parts of the developing world the gap is not as wide. Men of all ages in industrialised countries run a greater risk of dying than women. This is particularly true of young men and those over 60.
At first, it was thought that this difference had biological origins and might, for example, be due to sex hormones. However, a study carried out in German monasteries and convents found that monks lived almost as long as nuns and other women. It seems clear that lifestyle and living conditions play a greater role in life expectancy than genetic differences.
The average life expectancy of men is probably shorter than that of women because they run more risks and are more weighed down by stress and work – unless they happen to live in a monastery. The fact that men generally pay less attention to their health may also be significant.
Is there a longevity gene?
Although the maximum life span for the human species is determined by the human genotype, a person’s individual life expectancy is not only a matter of genes. Nutrition and other environmental factors have a strong influence on how long we live. Together with genes, these factors can dictate how many free radicals – which damage cells - are created as the body generates energy, and how effectively these can be rendered harmless and the damage repaired.
In flies, worms and mice, various genes have been discovered which have a particularly marked effect on life span. By modifying the way such ‘Methuselah genes’ act, scientists have succeeded in considerably prolonging the lives of animals. For example, gene activation in mice resulted in metabolic changes similar to those brought on by a life-prolonging starvation diet. Corresponding genes are also found in humans.
Some researchers believe that, with the help of newly developed pharmaceuticals, it will also be possible to one day extend the human life span.
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