HOW LONG CAN WE EXPECT TO LIVE?
The short and obvious answer is “not forever”. The reason for this is Evolution. Evolution is based on the propagation of beneficial characteristics through the survival of the best-fit individuals. That is, the fittest amongst us will have a higher chance to reproduce and pass their traits to the next generation. The flip side of this is that there is no evolutionary benefit associated with long-term survival of the individual past reproductive age.
IF WE CANNOT EXPECT TO LIVE FOREVER THEN, HOW LONG CAN WE EXPECT TO LIVE?
First, we need to talk about two terms, “lifespan” and “life expectancy”. On the one hand, lifespan is the average maximum time of life while life expectancy is the number of years that one can expect to live from birth or any other age. In other words, lifespan is the best case scenario while life expectancy depends on the circumstances and therefore changes over time.
OK THEN, WHAT IS THE LIFE SPAN AND LIFE EXPECTANCY FOR HUMANS?
At first blush, this seems like a simple enough question. Life expectancy depends on the time in History, part of the World one happens to live and grow up in, socio-economic circumstances, gender, and ethnicity, among other factors. Data gathered over the last ~150 years show that life expectancy has been increasing steadily due to the adoption of sanitation and advances in the prevention and treatment of infectious diseases. For example, life expectancy in 17th century England was only 35 years primarily because of the high rate of infant mortality. According to the World Health Organization, the world average life expectancy in 1900 was 31, 48 by 1950 and 67.2 years by 2010. There were however temporary dips in this trend because of major wars or disease pandemics; World War I and II, as well as the 1918 flu pandemic, are recent historical examples of well-documented reasons for the reversal of the positive trend in life expectancy.
On the question of lifespan, according to a 2009 report by the United Nations, the number of centenarians, that is people reaching 100 years of age, is increasing at a rate of almost 6% per year in industrialized countries. If this trend holds, the population of centenarians would be expected to double every 13 years.
Does this mean that we should expect life expectancy to continue to increase? Or is there a “hard-coded” maximum life-span for human beings?
I found this really funny video showing how humor can help us enjoy our golden years…
by: Adrian Vilalta, PhD