Human Lifespan Might Be About to Hit a Ceiling, Experts Say

The 20th century saw an impressive acceleration in the average lifespan of people worldwide. In 1900, the average life expectancy of a newborn child was barely over 30 years old—in 2021, that number had reached 71 years. Thanks to medical and technological advances, most of the previous century saw about three more years added every decade to the average lifespan of people in developed countries.

Many scientists predicted this “radical life extension,” as it was called, would continue indefinitely. Some even claimed that most people born today will live to be centenarians. In 1990, however, epidemiologist S. Jay Olshansky, currently at the University of Illinois Chicago, published a controversial study that pushed back against this notion. He argued that despite undeniable advances in the medical field, the rise in the average lifespan would decelerate and eventually settle at an average of around 85 years.

“In 1990, we predicted increases in life expectancy would slow down, and the effects of medical interventions, which we call Band-Aids, would have less and less of an effect on life expectancy,” Olshansky tells CNN’s Sandee LaMotte. “A lot of people disagreed with us,” he adds. “They said, ‘No, no, NO!’ Advances in medical and life-extending technologies will accelerate and will drag life expectancy along with it.”

Now, Olshanksy and his collaborators conducted another study, published in the journal Nature Aging on Monday. The result? He seems to have been right. The data shows that though human longevity is still increasing in developed countries, the rate of that increase is slowing, suggesting our species might be approaching a biological limit.

“We waited three decades to see what actually happened, and so we now know the answer, and that’s what’s in this paper,” Olshansky tells Gizmodo’s Ed Cara. “And the answer is exactly as we had predicted.”

To reach their conclusions, the researchers looked at data from 1990 to 2019 on the eight countries with the longest lifespans: Australia, France, Italy, Japan, South Korea, Spain and Switzerland. The researchers also included Hong Kong and the United States, even though the average lifespan in the U.S. isn’t close to the top ranking—and it has actually decreased in recent years, per a statement.

Overall, the analysis found that the rate of increase in average life expectancy in Australia, France, Italy, Japan, Spain, Switzerland and the U.S. slowed during the studied decades. South Korea and Hong Kong’s improvements were the only ones to keep pace with the predicted “radical life extension,” but researchers suspect this might be because their increase in life expectancy was concentrated in more recent years.

In 1990, life expectancy rose by about 2.5 years per decade, Mike Stobbe reports for the Associated Press. By the 2010s, that had decreased to 1.5 years—and to virtually zero years in the U.S.

To drive their point even further, the team calculated what life expectancy should be today if the scientists who resolutely supported “radical life extension” had been right. If that were the case, 6 percent of Japanese women today would live to 150 years old, and one in five would live past 120, reports Scientific American’s Rachel Nuwer. Needless to say, this hasn’t happened yet.

Luigi Ferrucci, scientific director at the National Institute on Aging who was not involved in the study, tells the New York Times’ Dana G. Smith that he doesn’t necessarily agree with its findings. Advances in preventative health could delay the onset of aging-related diseases, potentially lessening the damage “due to the biology of aging,” he says. But he adds that the average life span likely won’t increase if nothing changes.

Ultimately, scientists point out that this study supports shifting efforts toward slowing aging and increasing healthspan, per the statement—essentially, extending the length of time that a person is healthy, not just how long they are breathing.

“There are limits to how far out we can push out the envelope of human survival,” Olshansky tells Nature News’ David Adam. “If you live long enough, you run up against the biological process of aging.”

But this, he adds to CNN, can be seen as a good thing. “This is a consequence of success. It is not a consequence of failure. It’s a consequence of allowing people to live long enough to experience the biological process of aging, which now is the dominant risk factor.”

Margherita Bassi | READ MORE

Margherita Bassi is a freelance journalist and trilingual storyteller. Her work has appeared in publications including BBC Travel, Discover magazine, Live Science, Atlas Obscura and Hidden Compass.