Human life expectancy saw a remarkable increase in the last century. Babies born in 1900 had a significantly shorter life span compared to those born at the start of the 21st century, who could expect to live, on average, three decades longer, with many reaching their 100th birthdays. Essentially, throughout much of the century, every year added about three months to an individual's potential lifespan.

While some optimists in the longevity field believe this trend will continue steadily or even accelerate, others take a more pessimistic stance. They predict that a natural ceiling will be reached, with the average life expectancy in developed countries falling short of 100 years.

A recent study contributes to this ongoing debate by analyzing data from 1990 to 2019. The researchers examined life expectancy across eight countries known for their long-lived populations, as well as Hong Kong and the US, concluding that, despite advancements in healthcare, the increase in overall life expectancy is slowing down.

“Most people alive today at older ages are living on time that was manufactured by medicine,” stated S. Jay Olshansky, a prominent aging researcher at the University of Illinois. “However, these medical interventions are yielding fewer additional years of life, suggesting that the period of rapid increases in life expectancy has come to an end.”

The analysis indicates that only 15 percent of females and 5 percent of males are expected to reach the age of 100. The authors assert that unless the biological aging process is significantly slowed, substantial life extension is unlikely within this century.

This study has sparked intense discussions among scientists and investors in the longevity sector. Dmitri Jdanov and Domantas Jasilionis from the Max Planck Institute for Demographic Research noted, “One of the most intriguing and lively scientific disputes concerns the future of human lifespan.”

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A Divided Perspective

The concept of extending human life may seem like science fiction, but modern medicine has already made it a reality. Innovations in medical technology and public health measures have dramatically enhanced life expectancy over the past century.

Looking back to the late 19th and early 20th centuries, antibiotics were not a standard treatment for minor injuries, and vaccines against various contagious diseases were scarce. Handwashing practices in surgeries were not mandated until the 1980s, despite being recommended.

The recent surge in biomedical technologies fuels optimism regarding life extension. Advances such as engineered immune cells targeting previously untreatable cancers and organ transplants offer hope. Medical imaging techniques allow for early disease detection, reducing risks during pregnancy. If this pace of innovation continues, more breakthroughs may be forthcoming.

However, pessimists argue that human lifespan has a hard limit. Similar to physical structures, our bodies eventually deteriorate. As cells age, they accumulate toxic waste, affecting brain function. Organ systems struggle, and efforts to combat age-related diseases often provide only temporary relief.

“Our bodies don’t perform well when pushed beyond their warranty period,” Olshansky explained to Scientific American. “As people live longer, it’s like a game of Whac-a-Mole; each mole represents a different disease that arises as longevity increases.”

Assessing the Limits

Olshansky has expressed skepticism about radical life extension since 1990, when he predicted that gains in life expectancy would slow regardless of medical advances. He is curious about humanity's potential lifespan limit.

In 1990, his team hypothesized that humans might be approaching a life expectancy ceiling of around 85 years. However, some critics believed the initial study underestimated future medical innovations.

Nearly four decades later, the latest findings support his original hypothesis. The research examined death rates and life expectancies from 1990 to 2019 across the eight countries with the highest longevity, including South Korea, Japan, Australia, France, Italy, Switzerland, Sweden, and Spain, along with Hong Kong and the US. Data primarily came from the Human Mortality Database, which tracks health measures and life expectancy since 1950.

From 1950 to 2019, average life expectancy consistently increased across all populations. Yet, over the past decade, this growth has plateaued, particularly in the US.

South Korea and Hong Kong experienced milder declines in life expectancy. Nonetheless, only about 14 percent of female children and 4.5 percent of male children born in 2019 are expected to live to 100. In the US, the figures are even lower, with just over 3 percent of female children and 1 percent of males anticipated to reach that age.

This data suggests that if a man and a woman both reach 50 years of age, the woman is expected to live to an average of 90, while the man would likely reach 85.

“Our findings challenge the prevailing notion that humanity's natural longevity limit lies ahead of us—beyond our current life expectancy,” Olshansky stated.

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Future Considerations

Previous analyses indicate that no country has consistently increased life expectancy since the 19th century, but that doesn’t mean future records are impossible. The study emphasizes the need for further research into the biological processes of aging and why age-related diseases emerge.

“Insights into future longevity may come from studying exceptionally long-lived populations,” wrote Jdanov and Jasilionis. By examining the biology, diets, and lifelong habits of these "longevity vanguards," researchers can uncover underlying factors. Incorporating social variables, such as education, may also enhance predictive accuracy for broader populations.

Olshansky anticipates controversy surrounding these new findings. However, he urges the focus to shift from mere life extension to enhancing healthspan—the number of healthy years people can enjoy.

The research acknowledges that current strategies targeting age-related conditions, such as metformin and senolytics, were not considered in their projections. Such approaches could represent future avenues for exploration, as we have gained significant understanding of aging mechanisms compared to last century.

Olshansky concurs, stating, “There’s plenty of room for improvement. We can break through this glass ceiling of health and longevity with advancements in geroscience and efforts to slow aging’s effects.”