The Potential Problems of Living Longer (Tufts)

Many scientists are trying to determine just how much medical intervention can lengthen the human lifespan.

But Daniel Promislow, senior scientist and scientific advisor at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, is interested in a different question: If humans suddenly start living longer, what might the consequences be?

It’s something we all need to consider as more and more aging research labs work to identify pathways for countering age-related decline, paving the way to develop life-extending drugs, says Promislow, who has laid out his argument in “Lessons for Responsible Geroscience From the History of Longevity.”

What sparked the conversation for you around responsible aging research?

I had long been interested in the broader implications of the field. I go to a lot of aging meetings where researchers talk about the basic biology of aging, and potential ways to slow or delay aging through biological interventions. Not surprisingly, those meetings don’t include experts in public health, history, bioethics, or economics.

At the University of Washington, I met a Ph.D. student named Nicolai Wohns who wanted to talk to biologists who work on aging about ethics. Our conversations led us to co-author this article. We thought, “How do we place this whole world of gerotherapeutics in a philosophical and historical context?”

And we realized that the world itself is changing. In the last 150 years, improvements in agriculture, antibiotics, vaccines and many public health advances have doubled the average human lifespan. Much of this effect is thanks to our ability to prevent childhood infectious diseases. Geroscientists are now focused on trying to decrease or delay diseases that occur later in life. If they are successful, this could have enormous implications.

If a drug to treat aging were to become available, what problems could potentially arise?

There are issues surrounding equity and justice. Who has access to these drugs, and who might be denied access if they want them? What about the people who do take the drugs and suddenly have to support themselves financially for many more years than they had anticipated? We already know that many people in this country aren’t able to save enough money for retirement. Longer lifespans could put greater pressure on the Social Security system.

Beyond the economic consequences for the next generation, we should also ask about social implications. What if we had a pill that could greatly increase the chances of a 60 year-old living another 40 or 50 years or longer? Imagine if you took this pill, but your children and grandchildren wanted nothing to do with it. You could end up outliving even your grandchildren.

Geroscientists have often described as ‘ideal’ a scenario where people live to late age in a state of health as good as in their younger years, and then at some point—say, 100 years old—just don’t wake up. If science could get us there, what would that world look like, and how would we prepare for it?

In the paper that Nicolai and I wrote, we aren’t saying, “Here’s what’s going to happen.” At its heart, the paper is a first effort from Nicolai and me to call for people to come together and start to have these conversations, and to be really thoughtful about the issues.

Full article: The Potential Problems of Living Longer | Tufts Now

A Summary of Daniel’s paper: “Lessons for Responsible Geroscience From the History of Longevity.”

Introduction and Historical Trajectory of Longevity

The paper by Wohns and Promislow contextualizes contemporary geroscience within a historical framework, examining how public health, medicine, and economic growth transformed human lifespans over the past two centuries. Historically, global populations faced limited longevity due to high infant mortality and infectious diseases. For instance, US life expectancy at birth was only 39 years in 1860. However, public health initiatives, socioeconomic development, and scientific breakthroughs raised this metric to 70 years by 1960. These historical gains stemmed primarily from revolutions in sanitation and nutrition, alongside vaccines, antibiotics, and improved neonatal care. As infectious diseases declined, chronic conditions like cardiovascular disease and cancer became the leading causes of mortality, prompting advanced treatments that pushed US life expectancy to 78.4 years by 2023.

Reconceptualizing the “Natural” Human Lifespan

This dramatic expansion of life expectancy challenges traditional notions of a fixed, “natural” human lifespan. Quantitative genetics shows that heritable factors account for only 20% to 30% of individual lifespan variation, meaning environmental and behavioral factors determine the vast majority. The authors define the “natural” lifespan as the maximum longevity achieved under optimal environmental conditions for a specific genotype. This framework positions aging as a fundamentally malleable and modifiable condition. While this perspective mirrors classical advice from Hippocrates and Cicero regarding lifestyle and environment, modern progress demonstrates that systemic societal alterations and scientific tools are necessary to actualize substantial, population-wide longevity gains.

Social and Systemic Dimensions of Lifespan Extension

The history of lifespan extension highlights key social and systemic dimensions of population health:

  • Collective Goods vs. Inequity: Broad public health measures historically benefited entire societies, yet unequal resource distribution has widened longevity disparities between rich and poor nations, as well as along racial lines.

  • Community Interdependence: Population-wide averages often mask internal disparities, underscoring that an individual’s lifespan remains deeply intertwined with community infrastructure and resources.

  • Systemic Consequences: Increased longevity triggers deep socioeconomic shifts, altering family structures, delaying childbearing, and increasing retiree-to-labor ratios that strain social security systems.

  • Lifespan-Healthspan Disconnect: Historically, gains in total lifespan have outpaced extensions of healthspan, forcing populations to manage chronic diseases for longer periods.

The Paradigmatic Shift of Gerotherapies

Traditional public health strategies face a statistical ceiling; eliminating all deaths from cancer and cardiovascular disease would still keep US life expectancy under 90 years. Geroscience offers a novel strategy by developing gerotherapies—such as senolytics, mTOR inhibitors, and cellular reprogramming via Yamanaka factors—to target the biology of aging itself. The authors identify three distinct features distinguishing gerotherapies from historical health interventions:

  • Targeting Late-Life Biology: Unlike traditional interventions focused on early-life survival, gerotherapies target biological mechanisms that manifest primarily in mid-life and old age.

  • Direct Intrinsic Modulation: Rather than indirectly mitigating extrinsic mortality risks by disrupting pathogen transmission (e.g., water chlorination), gerotherapies directly alter internal cellular and molecular aging pathways.

  • Individualized Delivery: Traditional public health relied on collective, population-wide interventions, whereas gerotherapies are conceptualized as individualized medical treatments tailored to single patients.

Lessons for Responsible Geroscience

To ensure ethical advancement, the authors present three lessons for responsible geroscience.

First, society must anticipate the demographic and socioeconomic disruptions caused by successful gerotherapies, requiring interdisciplinary collaboration across economics, sociology, and medicine.

Second, because gerotherapies are individualized, frameworks of equity and justice must govern access to prevent exacerbating existing social divisions.

Third, cutting-edge geroscience must not overshadow foundational public health initiatives. Crucial systemic measures—such as sanitation infrastructure, vaccination coverage, and reproductive care—face contemporary threats from political polarization, misinformation, and spending cuts.

Ultimately, responsible geroscience requires a dual commitment: innovating biological interventions to extend healthy life while preserving the foundational public health systems that safeguard entire communities.