Human Life Span
My girl friend and I got into a discussion about life
spans of humans, both historically and geographically. I have two basic
questions. First, do humans live longer now I comparison to 2000 years
ago? Next, what is the life span difference between a city dweller and
say a South American Indian living in the rain forest (not in houses)? if
you can help me answer this we would both appreciate the help.
It depends on what parameters you place on life span...average or maximum.
Average life span has dramatically increased over the past two thousand
years. Average life span can be lowered by a host of factors some of which
in modern times have been dramatically reduced. 2000 years ago average life
span is believed, by most, to have been in the 20's. This was in part
because of such things as, starvation, disease, and high infant mortality.
Even in the 1700's in the US it was still in the 20's. The 19th and 20th
century saw the most dramatic rise in average life span. Clean water for
cities, reduction in infant mortality and improvements in medical
intervention (e.g., antibiotics) played large roles.
Maximum life span is far more challenging to find. Since I got my Ph.D. in
this field, it has been somewhat of a controversy but most estimates of it
seem to have been rising over the past 20 years. In the journal* Science* a
few years ago there was an article on the "oldest" living humans (documented)
and I believe they were on the island of Sardinia. I think there is NO limit
to maximum human life span. In the future, it will be more and more feasible
to replace or rejuvenate "worn out" organs or organ systems to keep a person
alive. Consider if you will the possibility of downloading the entire
memories and personality of a human into a computer and then uploading this
into a human whose mind is a void...far out...but possible. It just depends
what you might consider an individual or human. As a biologist for over 30
years, I still have not found a satisfactory definition for an individual or
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Update: June 2012