Life Span Is Only Limited Without Intervention

Median life expectancy in the world today

We've known there is a 'natural' maximal human life span for a while, but it would be extraordinarily naive to believe it will always be so

In the latest study published in Nature, researchers claim that human life span has a fundamental limit of around 115. This has been widely publicised around various news platforms, and has proved highly controversial, with many taking sides or making rather grandiose claims about future trajectories. After observing trends in survival from 1900 onwards, the team discovered that maximal life span has plateaued; forming a ceiling at around 115-120 years. Jeanne Calment is so far the longest lived (verified) person in history, passing away at an extensive 122 years. Despite dying in 1997, no one has surpassed her title in over 10 years. The research repeats previous observations and analysis suggesting that without intervention there is indeed a limit to human life span, and that it is exceedingly rare to approach this limit at all; explaining why Calment remains unchallenged. 

“It is disheartening how many times the same mistake can be made in science and published in respectable journals” - James W. Vaupel, the director of the Max-Planck Odense Center on the Biodemography of Aging

Life expectancy is levelling out in developed nations

History repeats itself

While the observation in itself is unsurprising, the study and the majority of coverage on the topic have extrapolated the data further - predicting that no-one will ever peak beyond this inexorable time barrier. This is deeply regrettable and repeats many similar historical opinions echoing across history. Many experts in the past have claimed that humans would never be able to fly, never reach the moon and never be able to feed a population of billions (we have the agricultural capacity to do so, whether or not it is distributed sufficiently). Obviously all were incorrect, and it is highly improbable that this issue will be any different.

Life span is only defined without intervention

The striking predictability in life span difference between different species provides excellent evidence that life span is largely genetically determined. This therefore suggests humans have a similar life span 'cap', but this is really rather predictable and adds no new information into the mix. In other words, it's irrelevant whether there is a natural cap on life span, because in a world of antibiotics, organ transplants, gene therapy and IVF, do we really expect human health to remain static?   

The Bowhead whale may have an average life span of over 200 years. By studying organisms that have evolved more robust longevity mechanisms it's likely we can modify humans in a similar manner

Extending healthy years and maximal years

These concrete statements that human life span has hit an unbreakable wall are premature, but we must honestly acknowledge the challenges ahead. It is virtually impossible that human society will fail to innovate and evolve in the coming years, and we must therefore expect that medicine will continue to make advances as it always has done. It would actually be extremely inhuman for it not to do so.

It is also important to be clear that extending life span without retaining health is neither desirable or helpful. This unquestionably presents us with a significant challenge, but our track record is strong and our knowledge of biology grows daily. We shouldn't underestimate the extent of the barriers to progress, but we now have a rough outline of the changes occurring during the aging process and a number of robust animal studies in which both health span and life span were increased (through telomerase induction, senescent cell removal and gene deletion for example). Now, mice are not humans but the research shows us that life span is inherently malleable, if you have the tools to do so. 

A positive vision of the future

We know staggeringly more about the aging process than we did even 10 years ago, and while no one alive today knows how long it will take to make significant progress in field, it's one of the most pressing and moral causes in the world today. We live in a predominantly aging world, and one in which millions of elderly are suffering in dependence and chronic illness. We have two options: either leave them to die inhumanely, or do something about it. Aging and age-related disease are deeply interlocked. If we want to live a long time without experiencing cancer, Alzheimer's or cardiovascular disease (to name a few), then we have to intervene in the aging process itself. 

No one knows what the future holds, but we can look to the future with increasing optimism if we choose to do so 

There has been some opinion in news coverage that to overcome this 120 year barrier would require us to be somehow inhuman, but in fact it would be quintessentially human

It really wouldn't matter whether we had to tinker with a network of genes, go to the clinic for repeat cell therapy every decade or so, or even take regular drugs to keep us sprightly. Those with disabilities are no less human, those with novel mutations are no less human, and those that have undergone gene therapy are no less human. Humanity is not defined by a narrow subset of confining genes, and indeed no one can define for another what it means to be 'human', although they have certainly tried. Surely we are better defined by a will to overcome challenge, and a proactive approach to improving the world around us.  If clinging to a narrow definition of humanity hinders and harms us, then there is little benefit in doing so. 

Of course everyone has a different opinion on these matters, but I would suggest that hope and the will to improve the lives of strangers, those we love and our own lives is the most admirable trait we have. Does it really matter if it takes considerable intervention to improve our health and increase the precious years we have on this earth? Keeping humanity in a stagnant prison of limitation hurts us all and belittles our potential. Medicine began with the will to save lives and improve health; healthy life extension is simply the culmination of that sentiment.

 

 Robert Powles