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Is there a limit to Human Lifespans?

  1. Nov 4, 2011 #1
    2,000 years ago the average life expectancy for humans was 19 years old. I mean, can you image having to kick the bucket before you’re even old enough to drink?

    2,000 years later, with a little hand washing and a booster shot, you’ve got a pretty good chance of living to the ripe old age of 63. This average is for the whole world population. If you’re lucky enough to live in a developed country, which I’d guess you probably are since you’re reading this, your lifespan jumps considerably.

    Take Japan for instance, which has the longest average expectancy at 79.9, according to government figures. If you live in the US, however, expect to live to an average of 77.3.

    Separate the figures by gender, and men live to 72, while women live to 79, a whopping difference of seven years according to the 2001 CIA World Factbook.

    Can we really expect to live this long or longer? The key question here is not what is the average human lifespan, but what is the maximum human lifespan.

    In nature, there are quite a few examples of extreme lifespan. At 40,000-years the King's Holly shrub is the oldest living organism in the world. Located in a remote southwest corner of Tasmania, it is older than the last ice age.

    Also, look to bacteria, which are in essence immortal as they do not change their structure over time. Plus, there is the famous HeLa cells case. Henereta Lacks, died Oct. 4, 1951, cervical cancer, yet her cancer cells still live on. Research centers worldwide use her immortal cells for medical research. The cells of her cancer, known as HeLa cells were the first human cells discovered to grow and thrive outside of the human body. And they are still growing to this day, as they were instrumental in the cure for polio and may one day solve the problem of cancer itself.

    For the past few decades, scientist in polite circles have generally agreed upon the idea that humans couldn’t live much past 120. This theoretical lifespan limit has been tossed around so often, that it's hard to believe otherwise. Yet, is there any truth to this number? Well, it’s probably safe to say that few people, if anyone, have lived longer than 130 years, or at least the case has not been documented well enough to be granted passage into the honored halls of Guinness World Records.

    Jeanne Calment, the oldest person to ever to live, was a Frenchwoman who died in 1997 at 122 years. She rode a bicycle until the age of 100 and once met Vincent Van Gogh in her father's painting shop. Her longevity is linked to her genes, as her father lived to the age of 94 and her mother to the age of 86.

    According to Guinness, Japan is home to the world's oldest woman, Kamoto Hongo, who turned 115 this year; the oldest man, 113-year-old Yukichi Chuganji; and the community with the highest proportion of centenarians – 33 people per 100,000 in Okinawa.

    According to a longevity study conducted by John Wilmoth, a UC Berkeley associate, the "oldest age at death for humans has been rising for more than a century and shows no signs of leveling off."

    Wilmoth and fellow colleges in the US and Sweden, researched the national death records in Sweden and found an increase in the average maximum lifespan each year since 1861. This finding calls into question the 120 lifespan limit.

    "We have shown that the maximum life span is changing. It is not a biological constant. Whether or not this can go on indefinitely is difficult to say. There is no hint yet that the upward trend is slowing down," said Wilmoth.

    Wilmoth’s statements about maximum lifespan run counter to common wisdom that there’s a natural limit. “Those numbers are out of thin air... there is no scientific basis on which to estimate a fixed upper limit. Whether 115 or 120 years, it is a legend created by scientists who are quoting each other."

    The rising trend in lifespan is credited to improved “medical practice concerning heart disease, stroke, smoking cessation, and the development of new drugs.”

    "One of the assumptions is that life expectancy will rise a bit and then reach a ceiling it cannot go through” says Mr Oeppen, senior research associate at the Cambridge Group for the History of Population and Social Structure. "But people have been assuming that since the 1920s and it hasn't proved to be the case.”

    "If we were close to the ceiling we might expect the survival of Japanese women now to be improving at a slower rate. But the improvement in Japan is among the fastest in the world." Oeppen said, "I think there is a ceiling, but we don't know where it is. We haven't got there yet."

    Look for advancements in anti-aging research to come hot and heavy as the baby boom generation gets ready for their “golden years”. While scientists are far from having a cure for aging, there’s a concerted effort on the part of numerous scientist on many fronts. The potential cure for aging will likely come from one or more of the following:

    1. Genetic Manipulation
    With the human code now mapped, the race is on to find the anti-aging genes.

    2. Stem Cells
    While still a hot button issue, the potential here is enormous. Imagine growing a new heart from your own stem cell. Take a stem cell from your skin and harvest replacement organs without the dreaded problem of immune rejection from your body.

    3. MEMS and Nanotech
    With nanotech growing up, doctors are willing to look to Microelectromechanical System, MEMS and Nanotechnology for smaller and less evasive devices to monitor and repair aging cells and organs.

    Does all this add up to extremely long life? No one knows for sure, but who’s ready to bet against it?

    - Bruce J. Klein
     
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  3. Nov 4, 2011 #2

    atyy

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  4. Nov 4, 2011 #3

    Ryan_m_b

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  5. Nov 4, 2011 #4

    atyy

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  6. Nov 4, 2011 #5

    Ryan_m_b

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    Lol, I doubt this kind of problem will manifest for a long time. But true nevertheless.
     
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