Usually, when someone reaches the milestone of turning 100, it makes local headlines and might even go viral on social media — but what if that became the norm?
Reaching 100 years of age could become a more-likely scenario than you might think, especially given that humans are now living longer than ever before. After a temporary decline in life expectancy due to Covid-19, recent years have shown signs of recovery, but the long-term trajectory is still shaped by how we tackle chronic illness, mental health, and economic inequity.
And there might be some ways to dramatically extend the human lifespan even further: While there have been a number of studies in recent years, one that has arguably made the most waves was published in the journal Nature Communications in 2021. It concluded, among other things, that humans could live up to 150 years. Yes, you read that correctly.
Still, there’s the question of whether it would be a good idea to live that long, given that some diseases like cancer become more prevalent as we age. There are also plenty of common physical conditions — like hearing loss, cataracts, and neck and back pain — that can make getting older uncomfortable, to say the least.
To better understand the complexities behind potentially living longer than ever before, we turned to demographer Mark Mather and Heather Whitson, M.D. of the Duke Aging Center.
What is the average life expectancy?
Since the mid-1800s, life expectancy has been increasing by an average of six hours a day — a remarkable pace driven largely by advances in medicine, sanitation, and nutrition. By the year 2100, most people are expected to live to be 82 years old (the current worldwide average is about 73). But even that estimate might prove conservative.
“Most of the improvements we’ve seen in human lifespan through the course of human history have been due to improvements in public health and standards of living,” says Mather, associate vice president of U.S. programs at the nonprofit Population Reference Bureau.
According to the Stanford Center on Longevity, living to 100 will become “commonplace” by the middle of this century, continuing a trend that saw life expectancy double between 1900 and 2000, a leap greater than all prior millennia of human evolution combined. In sum, the 100-year life is no longer a fantasy: It could be a fast-approaching reality.
In the U.S., life expectancy has begun to rebound slightly from recent lows, reaching 78.4 in 2023, though it still remains just shy of the pre-pandemic high of 78.8 in 2019.
Is there a hard limit on how long humans can live?
If the study in Nature Communications is anything to go by, there is a cap on how long humans can live — barring any disease or accidental injuries, scientists estimate that to be somewhere between 120 and 150 years old. (And, believe it or not, they came up with this estimate by counting blood cells and footsteps, and observing how both were connected to the body’s ability to recover from exertion.)
Does stress have anything to do with how long you live?
It has been well-documented that chronic stress can have a negative effect on your health, but it can also shorten your life expectancy. In fact, a 2020 study from the Finnish Institute for Health and Welfare found that it can shave off at least 2.8 years.
Dr. Whitson agrees, saying longevity is all about how well the body can respond to common life stressors, such as illness or a lack of sleep. “Much of our longevity and successful aging depends on how we respond to stressors from the environment,” she explains. “So that could be anything from an infection or an injury or even a new disease.” As the researchers in the Nature Communications study wrote, “If you do not target the loss of resilience, any medical intervention will fail.”
What are the different types of aging?
Even though the physical aspects of growing old, such as getting wrinkles or moving slower, often get a lot of focus, there are actually four types of aging: Chronological, appearance, biological, and mental. All can provide various insights into the aging process, but scientists in the Nature Communications study used biological age to predict the onset of diseases and determine humans’ maximum lifespan.
The main distinction when it comes to biological age is that it’s used to describe how old a person seems rather than how old a person actually is, chronologically. It’s also more difficult to quantify, because instead of the number of birthdays that pass, biological age points to what’s happening at a molecular and cellular level.
“The exciting part about that is if we can figure out at the molecular level what’s happening, it opens up opportunities for drug treatments that would directly attack the aging process itself,” Dr. Whitson tells us.
Can aging ever be reversed?
While none of us can stop the process of growing older, scientists believe that by reducing people’s biological age, they can extend the human’s average lifespan.
Dr. Whitson points out that lifestyle factors like diet, exercise, and sleeping habits can make all the difference when it comes to living longer. The Lancet medical journal reported that you can slash your mortality risk by as much as 50 percent by walking 7,000 steps a day.
And when it comes to optimum healthy habits, what you eat can make a serious impact. “The two main factors would be physical activity and a healthy diet,” Dr. Whitson tells us. “By ‘healthy diet,’ I mean that we probably have way too many carbohydrates in our normal diet, and those trigger all sorts of processes in the body that have now been associated with a poor pace of aging.”
What are some of the benefits and drawbacks of living longer?
One of the most obvious benefits of living longer is the familial aspect: It would allow generations to know their loved ones, rather than a memory of them. For instance, Mather’s own grandmother lived to be almost 108 years old, and got to know many of her great-grandchildren before she died. But Mather said that at a certain point, she started to run out of money and just being able to survive — from a financial standpoint — was extremely challenging.
“We need to address not just providing medications that will keep someone alive, but making sure that they’re entering their older years healthy and with the resources that they need,” he tells us.
Similarly, Dr. Whitson agrees that various inequities, like what we saw during the pandemic among minority populations, could become even more pronounced were people to live longer on average, and pointed out that these types of chronic stressors, such as racism, “take a toll.” She also added that there’s a difference between living and living well.
“A lot of people talk about the term ‘healthspan,’ meaning how many years of healthy life you have. We shouldn’t focus so much on extending the lifespan, but rather extending the healthspan,” she tells us. “You wouldn’t want to extend your lifespan if it meant that you drew out that part toward the end, where people have lost functions that are important to them.”
But if medical inventions and technological breakthroughs allow scientists to slow down the process of biological aging, we wouldn’t have to choose between quality or length of life. Both Peter Fedichev, the lead author of the Nature Communications study, and Dr. Whitson predict that this will be feasible within the next few years.
“Right now, there are trials for pharmaceuticals that could potentially slow down biological aging,” Dr. Whitson tells us. “Those trials are looking at ‘old’ medicines like metformin, which is a common medication for diabetes, and newer medications that work as senolytics [drugs which eliminate the cells that create inflammation and aging], or on other pathways. If those trials are successful, then it’s definitely conceivable that drugs could be marketed within five years as anti-aging treatments.”
