- Human life expectancy has seen a continuous rise since the 19th
century due to various reasons.
- Babies born in the United States today can hope to live upto 79
years, as compared to only 47 years in 1900.
- The 'maximum duration of life' or the maximum age to which the
oldest people could live has also increased since the 1970's.
- Researchers opine that the ceiling to maximum human lifespan has
already been achieved and further increase may not be possible.
Human lifespan has reached its maximum, and it may not be possible
to extend it further feel scientists at the
Albert Einstein College of Medicine, following a recent study.
Life Expectancy Over the Last Two Centuries Life expectancy has been continuously rising
since the 19th century
due to major
advances in the field of medicine such as treatment of infectious diseases,
advances in public health, better diet and improved access to health care.
‘Maximum human lifespan may have been achieved. Focus should now be on increasing health span.’
A baby born in the United States today can be expected to live to nearly
80 years, as against only 47 years in 1900
Such improved life expectancy is seen in many countries worldwide. In addition,
the 'maximum duration of life' or the maximum age to which the oldest people
could possibly live has also increased since the 1970's.
Data Analysed and What They Show
Dr. Vijg, senior author of the study and
professor at Einstein along with his team, analyzed data from the Human
Mortality Database, which compiles population and mortality related data from
more than 40 countries.
These countries have shown a reduction in late-life mortality since 1900
: The proportion
of each birth cohort (i.e., people born in a particular year) who live up to
old age (defined as 70 years and above) rose along with their calendar year of
birth, suggesting a continuing increase in average life expectancy.
However, when the
researchers studied improvements in
survival since 1900 for people aged 100 and above
, it was seen that increases in survival peaked at around 100
years of age and then fell rapidly
, irrespective of the year people were
born. "This finding indicates diminishing gains in reducing late-life
mortality and a possible limit to human lifespan," said Dr. Vijg.
He and his colleagues
also studied another parameter, namely, "maximum
reported age at death"
data from the International Database on
Longevity. They concentrated on people verified as living up to age 110 or
older between 1968 and 2006 in the four countries (the U.S., France, Japan and
the U.K.) which have the largest number of long-lived individuals.
Age at death for these supercentenarians rose rapidly between the 1970s
and early 1990s but hit a plateau around 1995
- further proof that lifespan may have reached its limit. This plateau, the researchers
note, occurred close to 1997--the year of death of 122-year-old French woman
Jeanne Calment, who attained the maximum documented lifespan of any person till
date in history.
Numbers Arrived at From the Analyzed Data
maximum-reported-age-at-death data, the Einstein researchers determined that
the average maximum human lifespan
was around 115 years
- allowing for
record-oldest individuals infrequently living longer or shorter than 115 years.
(Jeanne Calment, they concluded, was outside the statistical range.) Also, the
researchers calculated that the absolute
limit of human lifespan was 125 years
. In other words, the probability in a
given year of seeing one person survive to 125 years anywhere in the world is
less than 1 in 10,000.
Maximum Lifespan Has Been Attained - What Next
against infectious and chronic diseases may continue boosting average life
expectancy, but not maximum lifespan," said Dr. Vijg. "While it's
conceivable that therapeutic breakthroughs might extend human longevity beyond
the limits we've calculated, such advances would need to overwhelm the many
genetic variants that appear to collectively determine the human lifespan.
Perhaps resources now being spent to
increase lifespan should instead go to lengthening health span
duration of old age spent in good health."
Though it may not be
possible or even worthwhile in further prolonging lifespan, newer technologies
such as stem cells, genetic manipulation, and smaller mechanical devices to
monitor and repair aging
hold out hope to those who yearn for immortality.
- Human Lifespan - Is There a Limit? - (http://www.longecity.org/forum/topic/680-human-lifespan-is-there-a-limit-bruce-klein/)