The Quest to Live Forever: What is the Limit to the Human Lifespan?

Mankind has long been fascinated with the pursuit of prolonging our life. The idea of living longer or even gaining immortality has featured in legends and has over the centuries been the obsession of countless mystics, philosophers, doctors, authors, and great thinkers. Indeed the desire to evade death and escape our own imminent mortality has consumed us since time unremembered. Yet as far as we have come along with our vast medical technology and advanced civilization, there lingers the question, are we even meant to be able to attain the expansive lifespans we yearn for? Do we even have the potential within us to cheat the inexorable approach of aging, deterioration, and death? Do we have some insurmountable, built-in limit to our longevity or is it essentially without borders? In recent years this has become a hot topic of debate, with researchers clashing on the topic of what our bodies’ capacity for longer lifespans is and just how far we can realistically push beyond our mortality.

In order to look into the possibility of greatly prolonged lifespans it is important to first consider what the known maximum lifespan of humans has been estimated to be. There have indeed been incredible milestones set for longevity in humans, with the oldest confirmed person to have ever lived being a French woman named Jeanne Calment (1875-1997), who lived to the impressive age of 122. Others joining the ranks of some of the oldest humans who have ever lived are Emma Morano, of Italy (1899 –2017) who lived to the ripe old age of 117 years and 137 days, Susannah Mushatt Jones (1899 – 2016), who lived to be 116 and is notable for having done so while maintaining an eyebrow raising habit of eating bacon every day, as well as Ellen “Dolly” Gibb, of North Bay, Canada, who has lived to be 112 .

Jeanne Calment

While these cases are admittedly exceptionally rare, overall human lifespan has steadily increased over the years, and with such incredible records being made in human longevity there has of course been scientific interest in just how long humans are actually physically capable of living. In the coming years, will we see people living even longer, up to 125 years old or even beyond? One recent widely publicized and hotly debated report was made in the October 2016 issue of the scientific journal Nature, by a group of scientists led by a Jan Vijg, a geneticist at Albert Einstein College of Medicine in New York, and including colleagues Xiao Dong, Brandon Milholland, who claimed that they had conclusively found that the upper, impenetrable ceiling for human lifespan was 115 years, with the few cases of those living longer being merely an anomaly.

In order to come to this conclusion, Vijg and his team analyzed the International Database on Longevity, a vast store of data and figures on the aging trends of 41 different countries. In particular, the team looked at the data for the United States, the United Kingdom, France and Japan, and they found that while the number of centarians and new record breakers for age increased every year since the dawn of the 20th century, this trend oddly plateaued in the 1980s before grinding to a halt in the 1990s. It was expected that if there was no biological limit to the human lifespan, then there would be ever older people all the way up until the present, especially with ever improving medical care and better general nutrition, yet from the 1990s on the number of record breakers abruptly stops. Vijg surmised that this meant that there was a natural barrier in place to how long we are physically capable of living, roughly 115 years old, and that we have already reached it. Vijg would say:

When Jeanne Calment died, I really thought that this was the beginning of something very dramatic. If anything you would have expected more Jeanne Calments in recent years, but there aren’t. I can see that it’s very depressing when you find out that we can never get older than 115 years on average.

Jan Vijg

So is that it? Are we doomed to face a cap of 115 years, or is this a barrier which we can somehow punch through? This report and Vijg’s findings were widely publicized in the media, and immediately sparked a firestorm of heated debate and controversy within the medical community, with several other teams of researchers stepping in to criticize, refute and challenge this conclusion, as well as offer up their own contradictory findings. Some of this criticism was quite scathing, with statisticians being among the first to jump on the report, claiming that Vijg had used flawed data, fudged the numbers, made assumptions and one-sided conclusions, and cherry-picked and mishandled the data. One PhD student from the University of Groningen, a Nick Brown, pointed out one of these flaws as being the fact that the team had partitioned the data into two arbitrary time periods – before and after 1995- and that they then used data that seemed to match their perception that there was a levelling off. In a rebuttal that he co-wrote, Brown said of the conclusions of Vijg’s team:

Apparently, they thought they had found a pattern, then they develop a theory to explain the pattern. Then, presto, the data matches the theory—well of course, because the theory was generated from [that] data. That’s a pretty fundamental bug in the way of doing science.

Other statisticians have claimed that there were other technical errors made by Vijg’s team in calculating their statistics, and have come to much different conclusions when analyzing similar but more robust data. One example is Siegfried Hekimi, a biologist at McGill University, who reanalyzed the data used by Vijg without splitting it into the two time periods and found that it was rather consistent with the idea that there was more than one lifespan trajectory and that in some of these there was little to no plateau, suggesting that human lifespan could very well keep on increasing into the foreseeable future. He has said “We just don’t know what the age limit might be,” and suggested that we may even be capable of reaching up to 150 years of age and up.

Maarten Rozing, a gerontology researcher at the University of Copenhagen in Denmark, has also reevaluated the data and found that there is no evidence that the human lifespan has a 115 year cap, and has also claimed that Vijg made errors in his calculations. Based on his findings, Rozing has said that human ageing is more malleable than previously thought and that there is no real evidence of some sort of “biological clock” that limits how old we can get. He has also said of Vijg’s work, “It’s an extreme claim that they make that there is a limit to human lifespan, and I think an extreme claim deserves extreme scrutiny.” It has further been pointed out that Vijg’s team based many of their assumptions on decline in further longevity on the rather scant data of Calment and just eleven others. Rudi Westendorp, Professor of Healthy Ageing at the University of Copenhagen and former Professor of Geriatric Medicine in Leiden, said of Vijg’s findings:

Vijg is focusing only on the small group that achieves extreme longevity; it’s like looking at Olympic medallist Sven Kramer and drawing conclusions about the development of Dutch speedskating. Studies that examine a much larger pool of people in advanced old age show that the life expectancy of people, even the very oldest, continues to increase. All the available data says that the oldest individuals still living just keep getting older – and are in better condition as well. I honestly don’t get it. Nature should never have published this (Vijg’s report).

Various other scientists have stepped in to refute Vijg’s findings as well. Other teams of scientists have also put forth their own findings into the debate, including one team of researchers from the Netherlands Interdisciplinary Demographic Institute who also published their work in Nature. In this case, the team focused on statistics of Japanese women, a demographic renowned for their extreme longevity, and using mathematical models came to the conclusion that the overall human lifespan was indeed increasing, even projecting that by 2070 we will have reached a new maximum lifespan of 125 years and beyond.

This is not the end of the criticism by a long shot. One of the more vocal and scorching critics of the paper has been James Vaupel, a demographer at the Max Planck Odense Center on the Biodemography of Aging in Denmark, who also happens to have cofounded the very database that Vijg and associates used for their study. Vaupel says that there is no clear or apparent set expiration date for human lifespans, and he does not mince words when he says of Vijg’s report:

It’s the worst piece of research I’ve ever read in Nature magazine. I was outraged that Nature, a journal I highly respect, would publish such a travesty. The evidence points towards no looming limit. At present the balance of the evidence suggests that if there is a limit it is above 120, perhaps much above – and perhaps there is not a limit at all.

Harsh words indeed. For his part, Vijg himself has stood by his data and findings even in the face of this blistering response, and has suggested that such ire and criticism are the result of misreading his report and may also stem from his critics’ unwillingness to face their own imminent mortality. For his part he has generally been just as rabid in his responses, showing just how heated the debate has truly become, saying:

I guess the main message is that a lot of people have difficulty accepting that everything now points toward an end in the increase of maximum lifespan. They try to come up with intricate models to show that mortality is actually decreasing with very old age. It’s worse than science fiction. We may be able to do that at some point, as I say, by the way, at the end of my paper. But if we are not able to do that because aging turns out to be still very mysterious, or a process that we cannot really intervene with, then we are stuck with a real maximum lifespan that fluctuates around 115. Accept it.

Regardless of who is right or wrong, we are still left with the question of just how long can we possibly expect to live? Is it 115 as Vijg predicts? 125? Even longer? Is there some internal biological programming that has decided our maximum natural limit, or can this be extended somehow, possibly indefinitely? If so how and for how long? If there is indeed some biological ceiling to lifespan, then where does it truly lie and can we find a way to beat it? These are things that we will likely continue to shed light on with further study, and which are likely going to be hotly debated and discussed among scientists for some time to come. Parminder Raina, scientific director of the McMaster Institute for Research on Aging, has said of this ongoing journey of discussion and discovery:

People are moving into age 100, but we have no idea where that will end. Will these people continue to live longer and longer, or is there a certain limit to life expectancy? I think it’s an open scientific debate.

For now the answer to the issue seems to ultimately be “we don’t really know,” and this is doubtlessly an area that will be pursued intensely in the coming years. Whether we indeed have some immovable biological time limit or not, whether we are doomed to face the fact that our time is set, or have limitless potential to live for untold lengths of time, there will certainly be people who will keep trying to push beyond the barrier of age. People will keep on trying, refusing to bow to our mortality, defying death, just as we have done for centuries and probably always will.