The Limits of Human Lifespan: Dr. Jay Olshansky on Aging, Healthspan & the Future of Longevity Science

This episode of "Longevity by Design," hosted by Dr. Gil Blander, features renowned biodemographer and gerontologist Dr. Jay Olshansky, a professor at the School of Public Health at the University of Illinois at Chicago and co-founder of Lapidus Solution. The discussion delves into the fascinating trajectory of human life expectancy, exploring the reasons for its dramatic increase over the past century, the current observable slowdown, and the biological and societal factors that shape how long we live. Dr. Olshansky shares insights from his decades of research, including his predictions on the upper limits of human longevity and what it would take to surpass them. This episode is highly relevant for anyone interested in the science of aging, public health, and the pursuit of a longer, healthier life, offering a data-driven perspective on a topic often clouded by hype.

Key Insights

• The significant leap in life expectancy during the early 20th century (from 40-50 years to around 80) was primarily driven by dramatic reductions in infant, child, and maternal mortality due to public health advancements, vaccines, and antibiotics.
• Dr. Olshansky's research, starting in 1990, predicted that life expectancy would eventually slow down and level off (around 85-90 years on average) because an increasing proportion of the population would survive to ages where the currently immutable biological process of aging becomes the primary determinant of mortality.
• Even if all major diseases like cancer and heart disease were cured today, average life expectancy would only increase by a few years, not lead to immortality, due to the underlying aging process. Further substantial gains require interventions that directly target and slow aging itself.
• There are significant global and intra-national disparities in life expectancy. Factors like socioeconomic status, education, access to healthcare, and healthy environments (the "social determinants of health") play a crucial role, as illustrated by stark differences within cities like Chicago.
• While scientific breakthroughs to slow aging are the ultimate goal for radical life extension, individuals currently have considerable power to influence their healthspan and lifespan through healthy lifestyle choices: consistent exercise, a balanced diet, avoiding harmful behaviors (smoking, excessive alcohol), and regular medical monitoring.
• The "disease model" of extending life by tackling individual ailments is reaching its limits of effectiveness. The next longevity revolution will likely come from understanding and modulating the fundamental biological processes of aging.
• Women consistently live longer than men across most species, a phenomenon that begins in utero. While the exact mechanisms are still debated, it appears to be a deep-seated biological difference, likely linked to reproduction and evolutionary pressures.

The First Longevity Revolution and Its Inherent Limits

Dr. Olshansky began by explaining the "first longevity revolution" of the early 20th century. Life expectancy at birth, which hovered around 40-50 years globally in 1900, saw a "quantum leap." This wasn't because people in 1900 didn't live to old age (many did reach their 60s, 70s, and 80s), but because high infant, child, and maternal mortality dragged the average down. The revolution came from drastically reducing these early-age deaths through public health measures, sanitation, vaccines, and antibiotics. This pushed average life expectancy up towards 80 by the latter part of the 20th century.

However, as early as 1990, Dr. Olshansky and his colleague Bruce Carnes published a seminal paper in Science arguing that these gains would inevitably slow down. Their calculations showed that even eliminating major killers like cancer or heart disease would only add a few years to average life expectancy. The reason? The underlying biological process of aging. "If you cure everything, how come we don't live forever?" Dr. Olshansky posed. "The answer is, the underlying biological process of aging gets in the way." They hypothesized that once 80-85% of the population survived long enough to be "exposed" to this fundamental aging process, life expectancy would plateau around 85 years (perhaps 88 for women, 82 for men). This concept, termed "life table entropy," signifies that it becomes progressively harder to eke out additional years of average life expectancy as the population ages.

The Current Slowdown and the "Glass Ceiling" of Aging

A recent paper by Dr. Olshansky in Nature Aging confirmed their earlier predictions. By analyzing the 10 longest-lived populations globally, they found definitive evidence of this slowdown. While the plateau might be slightly higher now (perhaps closer to 87-90 for women, 84 for men), it's not 100, and the vast majority are not reaching a century. He emphasized that this isn't a forecast but a "reverse engineered" calculation based on what mortality reductions would be necessary to achieve higher averages—reductions that become increasingly unrealistic without tackling aging itself.

Dr. Olshansky used an analogy: asking if humans can run a one-minute mile. The answer is no, because "mechanically, our bodies aren't really designed to run that fast." Similarly, our current biology isn't designed for radical life extension beyond a certain point without fundamental changes. He described this limit not as a brick wall but a "glass ceiling," suggesting that scientific interventions targeting the aging process itself hold the potential to break through it. He stressed that natural selection could not have evolved a "program" for aging or death, leaving the door open for science to intervene.

Global Disparities: The Social Determinants of Health

The podcast highlighted significant variations in life expectancy across and within nations. Countries like Hong Kong and Japan boast some of the highest averages, while the United States lags, ranking around 45th or 50th. Dr. Olshansky attributed this, in part, to greater inequality in the U.S., where "large subgroups of the population...have very low life expectancies." He cited the stark example within his own city, Chicago, where neighborhoods just blocks apart can have life expectancy differences of 10-15 years. This disparity is driven by social determinants of health: education, income, access to quality food (the "food desert" phenomenon), and medical care. People in disadvantaged areas often lack the resources, time, or knowledge to adopt healthier lifestyles or manage chronic conditions effectively. In contrast, more affluent and educated populations, including U.S. presidents (who, contrary to popular belief, live significantly longer than average), benefit from better access to "manufactured time" through advanced healthcare and healthier living conditions.

Individual Agency: Maximizing Healthspan and Lifespan

Despite the biological limits, Dr. Olshansky emphasized the considerable power individuals have over their own health and longevity. He shared a personal anecdote of losing 20 pounds through diet and exercise to avoid taking statins, highlighting the efficacy of lifestyle modification. He advised listeners that "the greatest power we have is to shorten [life]," urging avoidance of harmful behaviors like smoking and excessive alcohol consumption. His top tips for healthspan and longevity today are exercise and diet, in that order, noting that exercise often naturally leads to healthier eating habits. He also stressed the importance of social connections, stating that social isolation can be as detrimental to mortality risk as having diabetes. Regular medical check-ups and adherence to medical advice, when necessary, are also crucial. He humorously noted, "I go to an eye doctor, I basically have as many body parts checked as I possibly can to detect any problems...because these bodies weren't designed for long-term use."

The Future of Longevity Science: Beyond "Patching"

Dr. Olshansky believes the current "disease model" of medicine, which focuses on treating individual illnesses, is "running out of steam" in terms of significantly extending average lifespan. While we have become adept at "patching" bodies together, these patches offer diminishing returns on overall longevity. The real breakthroughs, he argues, will come from targeting the aging process itself. He mentioned several promising research avenues, including the study of genetics in exceptionally long-lived individuals (like those studied by Nir Barzilai and Tom Perls), senolytics, metformin, and parabiosis, but cautioned that it's too early to know which will prove most effective. He is optimistic that multiple pathways will emerge.

This led to a discussion of his famous bet with Dr. Steven Austad, made in 2000, on whether a human alive in that year will still be alive and healthy in 2150 (i.e., reach 150 years of age). Dr. Olshansky, who wagered against it, remains confident he will win, citing the immense biological leap required to go from the current record of 122 years to 150. The initial $150 stake from each, wisely invested by Olshansky, is projected to be worth over a billion dollars by 2150, illustrating the power of long-term investment—a principle he believes applies equally to health.

Gender Differences and Other Intriguing Factors

The podcast touched upon why women generally live longer than men. Dr. Olshansky admitted, "I don't know the answer to this definitively," but noted it's a widespread phenomenon in the animal kingdom, likely with deep biological roots connected to reproduction. This difference manifests even in utero, with more male conceptions and a higher male mortality rate before birth and throughout early life, even before behavioral factors like risk-taking come into play. He also recounted his research debunking the myth that U.S. presidents age more rapidly due to stress. His findings showed they live significantly longer than their male contemporaries, benefiting from education, wealth, and exceptional lifelong medical care. While they might show superficial signs of stress like graying hair, "we don't die from gray hair and wrinkled skin."

Conclusion

Dr. Jay Olshansky provides a compelling, evidence-based overview of human longevity. While the 20th century saw unprecedented gains in life expectancy primarily through combating early-life mortality, we are now confronting the biological realities of aging. This has led to a slowdown in the rise of average life expectancy, a "glass ceiling" that can only be significantly breached by scientific interventions that directly modulate the aging process itself. Until such breakthroughs become widely available, Dr. Olshansky underscores the profound impact of individual choices—exercise, diet, avoiding harmful behaviors, maintaining social connections, and proactive medical care—on achieving a long and healthy life. The pursuit of longevity, he suggests, is shifting from merely treating diseases to understanding and influencing the fundamental mechanisms that govern our lifespan.