Live Long and Prosper

Gerontology experts weigh in on humans’ projected lifespans

Fact checked by Jim Lacy

Guessing how long the youngest generation will live feels like predicting your favorite sports team’s win record before the season begins. The more optimistic researchers now say humans born today could live to age 120; skeptics say most of us will top out somewhere in our 90s.

Douglas Vaughan, MD, director of the Potocsnak Longevity Institute at Northwestern University, falls in the latter camp. 

“I don’t think [120] is going to happen,” he says. “The idea that we could consistently extend the human health span by 40 years is a fantasy.”

Over the past century, science has been pivotal in extending life expectancy. Public health interventions such as vaccines, improved sanitation, antibiotics, and advances in cardiovascular and cancer care have all contributed to longer, healthier lives. 

But in the U.S., life expectancy has declined from 78.9 years in 2014 to 76.4 years in 2021. Vaughan cites societal issues such as the Covid-19 pandemic, drug overdoses, and long-standing health disparities as key drivers. 

In Chicago, for instance, life expectancy varies widely between neighborhoods just a few miles apart. In East Garfield Park, it’s 66 years; in the Loop, it’s 80. Vaughan attributes that gap not to genetics but to social determinants of health: environmental pollution, education, access to healthy food, and the chronic stress of racism. 

“Only about 10% of your lifespan is influenced by your genetics,” he says. “The rest is your environment.”

“We don’t need more research to help the disadvantaged live longer. We just need to get them access to what we already know works.”

Steven Austad, PhD, a professor and scientific director of the American Federation for Aging Research at the University of Alabama at Birmingham, agrees that lifestyle plays a major role in how we age. But he also believes humans could learn from our feathered friends.

In his book, Methuselah’s Zoo: What Nature Can Teach Us About Living Longer, Healthier Lives, Austad explores the surprising longevity of certain animals — particularly birds.

“Birds are the unsung longevity heroes of the animal kingdom,” Austad says. Despite their small size, high metabolic rates, and elevated body temperatures, species like the house sparrow can live up to 20 years in the wild. “We know mice lifespanlive maybe two years in lab conditions. But house sparrows, which are roughly the same size, live 10 times as long. That should grab our attention.”

Vaughan, meanwhile, believes the key to extending human life may lie in targeting the aging process itself. “Almost every adult disease — cancer, diabetes, heart disease — has age as its no. 1 risk factor. If we can slow aging, we delay disease,” he says.

That quest has sparked a booming longevity industry — from supplements and stem cell treatments to plasma infusions — all aimed at slowing, or even reversing, aging.

“We’re already one of the most successful species at aging,” Austad says. “Trying to get from 85 to 100 is like trying to make a world-class sprinter a little faster. It’s not easy. But it’s possible.”

Still, while the private sector races ahead with new aging interventions,public health infrastructure in the U.S. is eroding. 

Political leaders have chipped away at funding for public health departments and programs for decades. Now, deeper cuts at the federal level threaten the very existence of efforts that helped extend life in the first place.

“We need to rebuild and recommit,” Vaughan says.

Austad and Vaughan agree that ethical considerations loom large in the longevity debate. Access to life-extending innovations remains limited mainly to the privileged few who can afford it.

“The ethical goal should be to help everyone live a longer, healthier life,” Vaughan says. 

Austad adds: “We don’t need more research to help the disadvantaged live longer. We just need to get them access to what we already know works.”

So what does work? Proven scalable strategies: vaccinations, clean drinking water, and reduced air pollution all contribute to healthy aging on a population level. 

At the individual level, Vaughan points to stress management, adequate sleep, strong relationships, and regular physical activity.

The real question isn’t just how long humans can live — but how well. That means investing in proven public health tools, ensuring equitable access to care, and addressing the environmental and social factors that shape how we age. 

The road to a longer life might not lead to 120 for most, but it can stretch wider, enabling more of us to walk it together.

Originally published in the Summer/Fall 2025 print issue.