Can Human Lifespan Potentially Soar Beyond the Century Mark to Reach 100 Years?
It's an undeniable truth: Everyone eventually perishes. However, significant medical advancements, enhanced sanitation, and improved environmental protections have contributed to a steadily increasing life expectancy since the 19th century, barring a few epidemics. Recent data, however, suggests that this upward trend might be faltering.
A study published in Nature Aging last October, for instance, showed that while life expectancy in high-income nations like the U.S. has persistently increased, the pace of this growth has noticeably slowed over the past 30 years. Furthermore, the likelihood of individuals reaching the age of 100 is still negligible; only 3.1% of women and 1.3% of men born in 2019 in the U.S. are estimated to become centenarians. The study's authors argue that humanity might be approaching the limitations of our inherent mortality, and that the current methods of treating age-related conditions such as cancer will provide minimal enhancements and small increments in longevity in the future.
Not everyone shares this pessimistic outlook on the future of aging, though. For this Giz Asks feature, we consulted several experts to discuss whether an average person might live beyond 100, and if there's an ultimate boundary to human longevity and how we might surpass it.
S. Jay OlshanskyProfessor of epidemiology and biostatistics at the University of Illinois at Chicago's School of Public Health; longevity researcher; and lead author of the Nature Aging paper.
An eternity is a very long time, so I can't provide an answer based on an indefinite time frame. What I can assure you, though, is that a life expectancy at birth of 100 is not feasible in this century for any national population. In fact, it's highly unlikely for most people currently living. Why am I so confident in this assertion?
The demographic indicator of life expectancy relies on mortality rates for all ages. The first innovation in longevity occurred by saving children from dying from communicable diseases. Life expectancy experienced rapid growth in the 20th century due to the addition of years to children's lives, but this source of improvement is only available once for a population—and it's already been achieved. Those saved from early death now enjoy the luxury of living a longer life. Humanity should be grateful for this gift of extended life. However, the relentless march of biological aging is now preventing further advancements. As long as the aging process remains constant, and larger sections of each birth cohort encounter this inescapable force of mortality, growth in life expectancy must gradually decelerate. Our study has proven that this trend has been occurring for the past three decades, with solid evidence to back it up.
The critical question here is, what might the future hold? One issue that must be addressed immediately is whether treating diseases as we do now—one at a time, ignoring their interconnectedness—will enable a life expectancy at birth of 100. The answer is a resounding no. A study we published in 1990 demonstrated that the near-elimination of major fatal diseases would not make humanity immortal and would not even lead to a life expectancy surpassing 100. Human longevity is influenced by the cumulative impact of multiple medical conditions at advanced ages, making survivorship akin to a game of whack-a-mole—if you manage to eradicate one disease, two others will soon emerge.
What about the development of gerotherapeutics---therapies focused on slowing aging and extending healthy lifespan---that might slow the aging process? I personally am inspired by the potential, but the challenge here is that achieving a life expectancy at birth of 100 would necessitate reducing death rates from all causes at all ages by over 80%. Such substantial reductions won't happen overnight; it takes time to develop and test these treatments for safety and efficacy; there are concerns about the fair distribution of such interventions; and it's virtually impossible to validate empirically that any gerotherapeutic will yield significant changes in life expectancy within a short time frame. Even if science developed a treatment that could extend life to 120 or beyond, it would be difficult to prove, empirically, that this would result in a population-wide life expectancy of 100—even if this hypothetical therapy became available right now.
So, is it theoretically possible for a national population to achieve a life expectancy at birth of 100 years? In theory, yes; evolution did not create longevity time bombs that detonate at specific ages beyond which humans live today. However, there are no corresponding evolutionary constraints for humans to run a mile in one minute—but it's highly unlikely given our current physiological design. The same is true of life expectancy; the only way to achieve a life expectancy at birth of 100 is through groundbreaking medical or scientific innovations that simultaneously influence every aspect of aging (both body and mind), but even if this happened before our eyes today, we would lack the means to empirically justify a life expectancy of 100.
One of the queries we aimed to explore with centenarians was: Do they fall ill when everyone else does, starting around the age of 60? Would they be sick for another 40 years, which wouldn't be ideal. But we discovered the opposite; we discovered that their longevity and health went hand in hand. They would contract diseases around 30 to 50 years after other people did. And it's not just that they're living healthier for longer, there's a decrease in morbidity. Meaning, if they had a disease, it would last for a brief period at the end of their lives. About 30% of them die without taking any medication and without having any disease. So, is it possible for humans to be healthy for 100 years? Yes, and it's not the majority, but there are hundreds in my study, and probably thousands worldwide.
This recent study, however, appears to suggest, 'No, you can't live past 88.' This study is written by demographers, who look at the past to predict the future. These authors are arguing against other demographers who have stated: "Life expectancy has increased linearly without stop for the past 150 years. Every 10 years, we live 10 years longer. But is there a limit? Jay Olshansky believes there is. In a 2016 Nature paper, data was analyzed and found that the maximum lifespan of humans as a species is around 115 years. That's not the top for everyone, but it's the statistical top. If the top is 115 years, and half of us live past 80, there's a limit, and it'll start to bend, because we're not increasing at a straight line. But the individuals in my study seem to have longevity genes that allow them to reach this limit. So we need to harness these genes and create medications for others to at least reach that stage."
Would it be possible to increase this limit in the future? The answer is probably, although I don't think it'll happen in my lifetime. Even in animals, we don't have proof that lifespan can be increased so dramatically. So while I don't believe we'll break this limit, I do believe if we die before 80, but we have 115 years of potential life, we should work on how to live into our 90s or 100s without illness. That's not only possible but likely.
The title of the Nature Aging paper is about radical life extension. For me, radical life extension is living over 150. Is that possible? No, because I believe there's a limit. But can we live longer and better? Certainly.
Preston Estep
Biologist; former chief scientific officer and co-founder of Veritas Genetics; chief scientist and founder of the nonprofit Rapid Deployment Vaccine Collaborative (RaDVac); and entrepreneur in biotech and artificial intelligence research.
The future of human longevity depends entirely on the future of AI. Let's briefly discuss why, because some of the more important dependencies on AI might seem remote, but I argue they are far more likely than the commonly imagined scenario of human scientists solving biological aging.
There are two main contributors to longevity advances: environmental and biomedical. Major advancements in public health and standard of living have driven past gains in average adult life expectancy. Biomedical advancements are now driving impressive gains and promise to increase the average; but whether or not the average will reach 100 years is uncertain due to concerns about previous accomplishments regressing. For example, anti-vaccine sentiment, combined with climate change and other pandemic drivers, threaten to further undermine longevity trends that were reversed by the SARS-CoV-2 pandemic. It's more likely that we'll see a fragmentation of the longevity distribution: the longevity of the wealthiest and most educated will continue to increase, while that of the least educated and anti-science segments of society will lag substantially, and possibly decrease.
As for increasing the upper limit of human longevity, there is no insurmountable physical barrier; but are radical life extension breakthroughs in biomedical science foreseeable? While there's no physical barrier, are radical life extension breakthroughs in biomedical science foreseeable? An instructive example comes from physics. The frontier of physics has been largely stalled for decades, suggesting that even the best human minds have reached an upper cognitive limit. Plus, the number of human-made problems that have the potential to reduce human longevity is increasing. To solve the many extremely complex problems required for radical life extension—and to grow and preserve the infrastructure of civilization necessary to support extreme longevity—human-level intelligence clearly is not up to the task.
Therefore, the only possible route to breaking through the upper bound of human longevity is superhuman artificial intelligence. As AI becomes substantially more intelligent than humans, many breakthroughs become possible that are currently impossible, including a substantial increase in the longevity of biological humans. But then some key questions arise. Will biology remain the substrate of choice, or will the fastest and most efficient path to extreme longevity (and superhuman intelligence and power) be to merge with AI?
I propose that integration is the most likely avenue, primarily due to the current fusion of humanity and AI. We're not blending on an individual or physical level. Instead, we're uniting in the digital realm, as our collective human character is being assimilated into digital computers. This data, obtained from internet interactions and media, serves as the foundation for the training of cutting-edge large language models.
The reason ChatGPT achieved such widespread success, even after numerous previous setbacks in generalized AI, is its remarkable human-like qualities. However, ChatGPT is merely the starting point for a significant AI transformation, attracting substantial investments to manufacture more capable and advanced entities. Future generations of AI will possess greater capabilities in logical reasoning, scientific discovery, and the engineering required for human-AI fusion. Moreover, self-improving AI will facilitate the development of improved technologies for transferring human consciousness, whether on a collective or individual scale, to non-biological mediums.
This path offers the most direct route to enhanced lifespan – potentially even immortality. Yet, it also empowers the development of technological innovations capable of extending biological lifespans, providing a previously uncharted range of alternatives, trade-offs, and dilemmas.
Despite the advancements in medical science and technology, the study suggests that the pace of life expectancy growth has slowed over the past 30 years, and it's unlikely for most people to live beyond 100 in this century.asyncronously, researchers are exploring the possibility of gerotherapeutics, therapies focused on slowing aging and extending healthy lifespan, which could potentially provide a means to surpass the current limitations of human longevity in the future.
