What is the limit to human life? A striking number explained

When Jeanne Calment died on August 4, 1997, she was 122 years and 165 days old. The supercentenarian — the name for the small group of people who live to be 110 — still holds the (still debated) record for the longest human life.

As the world’s human population swells, so do the odds that more people will live abnormally long lives. According to the Pew Research Center, the world’s centenarian population grew four-fold between 1990 and 2015. The number of people over 100 is expected to reach 3.7 million by 2050.

And while a new statistical analysis suggests that there is no limit to the human lifespan — and argues it’s theoretically possible a person could reach 130 years old — the concept of infinite longevity is more complicated than that.

The upper limit of human lifespan

Back in 2017, researchers were searching for the upper limit of the human lifespan. They used data from 285,000 Dutch residents who lived to be at least 92 years old. Ninety-seven percent of people died before their 97th birthday and 99.5 percent didn’t live past 107 years. They determined that once a person reaches 110, there’s a roughly 50-50 chance they’ll live to see their next birthday. Their predictions were published in the journal Extremes.

The authors of a new study, published Wednesday in the journal Royal Society Open Science, wanted to see if a newly released, much larger dataset yielded the same results. They pulled data on French and Italian supercentenarians, as well as semi-supercentenarians (those who live to 105 years), from the International Database on Longevity.

What they found mirrored the previous calculations: A person who has lived to be 110 years has about the same probability of reaching their 130th birthday as they do flipping a coin and getting heads 20 times in a row.

The chance is “about one in a million, which is very unlikely but not impossible,” lead researcher Anthony Davison, a professor of statistics at the Swiss Federal Institute of Technology in Lausanne, tells Inverse.

In theory, the mathematical prediction suggests there is no upper limit to the human lifespan. However, the data was limited to those who are already predisposed to live extraordinarily long lives.

“Our results apply to those aged over 105, so I’m unsure how this might be relevant to the average person,” Davison says.

How to live past 100

With very few exceptions, modern Homo sapiens do not live older than 115 years, S. Jay Olshansky tells Inverse. Olshansky is a professor of public health and research associate at the Center on Aging at the University of Chicago and was not involved in either study.

Davison and colleagues concluded that while it’s possible that, due to the growing number of people living beyond 100, one person may live to be 130 years old in the next century. But it’s not something we should expect to see in the near future.

“In these bodies, we are not going to make it to 150.”

While people living in Blue Zones — parts of the world where people live longer than average, like in Okinawa, Japan and Loma Linda, California — have lifestyles and diets that make them predisposed to living longer, Olshansky says supercentenarians can credit their age to genetics, not lifestyles.

“You can’t make it out to extreme old age without winning the genetic lottery at birth,” he says.

“If you ignore the biology that drives human longevity you’re going to miss the big picture and anyone who has claimed there is no upper limit to longevity is missing the big picture,” Olshansky explains.

Is it possible that someone could theoretically live to be decades older than the supposed 122-year record, but Olshansky says believing most people will live to be supercentenarians is liken to claiming that most people can run a four-minute mile because a handful of extraordinary athletes have.

On its own, the new calculation doesn’t change anything for humans hoping to live well into their golden years. While there’s no biological ‘off switch’ capping human life at a certain age, people still can’t live indefinitely.

One of the reasons is that the biological aging of any species is directly related to their reproductive window, and “we aren’t going to manipulate those genetically driven patterns anytime soon,” Olshansky says.

“In these bodies, we are not going to make it to 150,” he adds.

Why? A study published in May in Nature Communications calculated the human body’s progressive loss of resilience. The researchers estimated that after roughly 120 to 150 years of life, the body would no longer be able to repair itself after suffering normal stressors.

Essentially, it would break down.

What comes next — Earlier this month, founder of Amazon and Blue Origin CEO Jeff Bezos announced that he’d invested in a mysterious new start-up called Altos Labs. The company is exploring biological reprogramming technology that can slow human aging.

It’s not totally sci-fi. According to Olshansky, some scientists believe there is an aging reset at the time of conception since the age of the sperm and egg that create the new human are well beyond zero. This means hypothetically slowing or reversing the “aging clock” through epigenetic reprogramming.

He’s among a group of scientists who are trying to understand the mechanisms that allow sperm and an egg with biological ages of 20 or 30 years to form a new cell that has no trace of the age of the maternal and paternal cells. It may be that the biological age of reproductive cells is different from other cells in the body, or the phenomenon may be due to an aging reset.

The big question is whether or not we can use that reset function to recreate or slow biological aging. The technology may just be used in specific body parts, like the heart, that can’t work forever.

“I don’t know how it might influence length of life, but it’s all exciting work and that’s just the tip of the iceberg of research centered around slowing the biological aging process,” Olshansky says.

In the meantime, researchers at the Albert Einstein College of Medicine in New York and Boston University School of Medicine are closely studying the super long-lived to tease out what genes are unique to these people.

“We know there is a phenotype linked to exceptional longevity and it’s possible they will be able to discover some alleles,” Olshansky says. If they do, “we may be able to mimic that for the rest of the population.”

Perhaps that doesn’t mean living until you’re 130 — but it could mean living well for longer.

Abstract: We use a combination of extreme value statistics, survival analysis and computer-intensive methods to analyze the mortality of Italian and French semi-supercentenarians. After accounting for the effects of the sampling frame, extreme-value modeling leads to the conclusion that constant force of mortality beyond 108 years describes the data well and there is no evidence of differences between countries and cohorts. These findings are consistent with use of a Gompertz model and with previous analysis of the International Database on Longevity and suggest that any physical upper bound for the human lifespan is so large that it is unlikely to be approached. Power calculations make it implausible that there is an upper bound below 130 years. There is no evidence of differences in survival between women and men after age 108 in the Italian data and the International Database on Longevity, but survival is lower for men in the French data.