Is there a limit to Human Lifespans?

In summary, according to government figures, the average lifespan for humans is 77.3 years. However, if you're lucky enough to live in a developed country, your lifespan jumps considerably to an average of 79.9 years.
  • #1
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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
 
Biology news on Phys.org
  • #5
atyy said:
Oh, there are also scenarios like http://arxiv.org/abs/hep-th/0106109 (bottom of p16) which would limit human life span.

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

1. What factors contribute to human lifespan?

There are many factors that contribute to human lifespan, including genetics, lifestyle choices, environmental factors, and access to healthcare. Genetics play a significant role in determining lifespan, as some people may be more predisposed to certain diseases or have a longer lifespan due to their genes. Lifestyle choices such as diet, exercise, and avoiding harmful substances can also impact lifespan. Access to healthcare, including early detection and treatment of diseases, can also play a role in extending human lifespan.

2. Is there a maximum age that humans can live to?

Currently, there is no known maximum age that humans can live to. While the average lifespan has increased over time, there have been individuals who have lived well beyond the current average lifespan. However, it is important to note that there are natural limitations to human lifespan, such as the aging process and the potential for age-related diseases.

3. Can medical advancements increase human lifespan?

Medical advancements have played a significant role in increasing human lifespan over time. With advancements in technology and healthcare, diseases that were once fatal can now be treated, and preventative measures have been developed to prolong lifespan. However, it is important to note that while medical advancements can extend lifespan, they cannot completely eliminate natural limitations or reverse the aging process.

4. How does lifestyle affect human lifespan?

Lifestyle choices can have a significant impact on human lifespan. A healthy lifestyle, including a balanced diet, regular exercise, and avoiding harmful substances, can help prevent diseases and promote overall health and longevity. On the other hand, a sedentary lifestyle, poor diet, and substance abuse can increase the risk of developing diseases and decrease lifespan.

5. Are there any current efforts to extend human lifespan?

There are ongoing efforts to extend human lifespan, including research on genetics, technology, and healthcare. Some scientists are studying the genetics of long-lived individuals to identify possible genetic factors that contribute to a longer lifespan. Others are exploring the potential of technology, such as regenerative medicine, to repair and restore damaged tissues and organs. Additionally, there is ongoing research on age-related diseases and potential treatments to delay or prevent them. However, it is important to note that these efforts are still in the early stages, and there is no guarantee that they will result in a significant increase in human lifespan.

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