Human Lifespan May Have a Hard Ceiling, Research Suggests

Our longevity may actually turn out to have a hard limit. In a new study this week, scientists show that the long rise in our collective life expectancy seen during the 20th century has started to slow down as of late. The findings suggest that focusing on simply expanding our lifespan might be short-sighted, the researchers say.

Life expectancy at birth is a commonly used metric of an area’s overall health. It estimates how long the average person born in a particular year (2024, for example) would be expected to survive, given current trends in mortality among different age groups. Starting in the 20th century, life expectancy has steadily increased across the globe, thanks largely to major medical advances like increased sanitation and drugs like antibiotics. But Stuart Jay Olshansky and other researchers have now found that this rise has slowed in more recent decades—a phenomenon that Olshansky and his team first predicted would happen quite a while ago, to much criticism from other scientists.

“We waited three decades to see what actually happened, and so we now know the answer, and that’s what’s in this paper. And the answer is exactly as we had predicted,” Olshansky, a professor in the School of Public Health at the University of Illinois at Chicago who has long studied aging, told Gizmodo over the phone.

Olshansky’s team studied mortality data from countries with the highest life expectancies, including Japan, South Korea, Australia, France, and Spain; they also included the U.S. for comparison, which has had a life expectancy above most other countries, but also below many peer nations. They were particularly focused on studying the trends between 1990 to 2019.

Overall, they found that while life expectancy continued to tick up, the rate of increase has noticeably decelerated, particularly since 2010. They also found that few people born in 2019 in even these best-performing countries are expected to reach the age of 100, with about 12.8% of women and 4.4% of men likely to make it. In the U.S., the odds are even worse, with about 3.1% of women and 1.3% of men born in 2019 expected to make it to 100. The team’s findings were published Monday in Nature Aging.

“Of course, there were still improvements in life expectancy in the last three decades, but they slowed down considerably, and they slowed down during a time in which advances in medical technology accelerated,” Olshansky said. “So if indeed life-extending technologies and disease reduction were having the effect that some people thought they would, life expectancy should have accelerated upwards, and it did not. It, in fact, slowed down considerably so in the United States.”

For Olshansky, the takeaway message from this research is simple enough. As valuable as medicine has been in lengthening our lives up through today, these advances have typically focused on treating one specific age-related disease at a time, such as cancer or heart disease, rather than delaying the process of aging itself and the many harmful changes that come with it. He argues that we’ve already started to reach the barriers of our natural mortality, and that this disease-specific approach will only now provide diminishing returns and incremental boosts in longevity moving forward.

“The life that we live today in our modern world, where most people make it out past 65 and we have a lot of folks that make it into their 70s, 80s, 90s, and even some that make it to 100—it’s manufactured time, time that was manufactured by medical technology. And these have been extraordinary events that have occurred in medicine and public health. And we should be grateful and thankful that we get to live these lives, but the price we have to pay for it is heart disease, cancer, stroke and Alzheimer’s, and that’s where we are today,” he said. “We’re playing this game of Whack-a-Mole with aging-related diseases.”

On the positive side, Olshansky has seen significant progress in finding and developing treatments that might be able to more broadly interact with and delay the aging process (some studies have even highlighted already existing drugs like metformin as candidates). And he expects major discoveries and breakthroughs in the emerging field of geroscience to arrive in the near-future. But he adds that there shouldn’t be a singular focus on extending our lifespan, even if some of these treatments do end up doing that. Instead, there treatments should be tuned to improve our healthspan, or the amount of years we spend in relatively good health.

Olshansky also cautions against buying into the hype of many people today involved in the industry of anti-aging research, who commonly boast about near-miraculous treatments being right around the corner.

“There’s a lot of money being invested in this right now. There’s a lot of good science going on. There’s also a lot of embellishments and exaggeration, which is something that we need to be cognizant of. And I wish folks would stop exaggerating and telling people they’re all gonna live to 100 or 120 or 150—these sorts of claims of radical life extension associated with any of these interventions,” he said. “You don’t need embellishment and exaggeration to justify this effort to slow aging. The best justification is what happens if we don’t succeed? And if we don’t succeed, we’re not going to like what we see.”

We may never be able to truly discover the fountain of youth, but hopefully, there’s still plenty we can do to make our time we have on earth as peaceful and healthy as possible.