Humans are the longest-living mammals. The maximum human
life-span is 120 years, but the length of life varies a lot
from place to place.
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Overall, we
know a lot about the human population. Yet although we
know how long a newborn baby is statistically expected
to live, we cannot predict how long each individual newborn
will actually live. An accident or self-destructive life-style
can suddenly end the life of any person, independent of
their genes. |
Life expectancy has increased dramatically in the industrialised
world during the 20th century - from almost 50 years to now
nearly 80 years. The longest-living group are Japanese women,
who are expected to live 83 years.
The additional years of life have been gained by 'traditional'
methods, such as improved food supply, hygiene and medicine.
In that sense living longer is a human creation. Wild animals
hardly ever have the chance to age, because the weaker ones
will eventually be eaten up by their natural enemies.
The same dramatic increase in life expectancy is now taking
place in developing countries. This is mainly due to improvements
in the food supply, medicine and hygiene. By 2020 almost three
quarters of the world's elderly people (i.e. those over 60)
will live in developing countries.
For people in the industrialised world to now gain a further
dramatic increase in life expectancy is extremely unlikely
by lifestyle changes alone.
Only by finding a way to modify the ageing process, and by
making this discovery available to the entire population,
might life expectancy exceed 100 years.
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