As Biden faces questions about his age, researchers weigh in on working in your 80s

• Despite some voters' misgivings, President Joe Biden's age is less of an anomaly than a sign of the times, experts say.
• Workers 75 and older are the fastest-growing age group in the labor market.
• The 118th Congress, meanwhile, is one of the oldest in history. There are five senators who are 80 or older, including Bernie Sanders, 82, and Chuck Grassley, 90.

Should he prevail in the upcoming presidential election, President Joe Biden, 81, would become the nation's first octogenarian elected commander in chief.

Despite the misgivings that fact has sparked among some voters, Biden's age is less of an anomaly than a sign of the times, experts say.

"There are lots and lots of people who still work in their 80s," said Dr. Dennis Selkoe, a Harvard Medical School professor who has won awards for his advances in aging research. "It's more common than ever."

Indeed, workers 75 and older are the fastest-growing age group in the labor market, more than quadrupling in size since 1964, according to the Pew Research Center.

If former president Donald Trump win in November, he'd be 78 at that point, and would become the second U.S. president to serve in his 80s. The 118th Congress, meanwhile, is one of the oldest in history. There are currently five senators who are 80 or older, including Bernie Sanders, 82, and Chuck Grassley, 90.

"People are just living longer," said Joel Kramer, director of neuropsychology at the University of California San Francisco's Memory and Aging Center. "So you're going see a lot more people in their 80s and 90s who are rock stars."

(On a literal note, Mick Jagger, who turned 80 last summer, is on tour this year and expected to perform in 16 cities across the United States.)

More from Personal Finance:
Many think pensions key to achieving American Dream
How to avoid unexpected fees with payment apps
'Ghosting' gets more common in the job market

Still, Biden — already the oldest president in the nation's history — is dealing with the perception that his age is a problem.

Almost two-thirds, 62%, of voters say they have major concerns that Biden does not have the necessary mental and physical health to be president for a second term, according to a national NBC News poll conducted in January. The majority of those polled who voted for Biden in 2020 now say he's too old to be effective, a New York Times/Siena College poll recently found.

The White House did not respond to a request for comment.

But how valid are these worries? To find out, CNBC spoke to neurologists and aging experts about the human brain and our ability to work in our 80s.

'Occasional gaffes' do not reflect anything

The most recent blow Biden faced over his age came from the Feb. 8 special counsel's report about his handling of classified documents. Robert K. Hur wrote that no criminal charges against the president were warranted, but he referred to Biden as a "well-meaning, elderly man with a poor memory."

Shortly after those findings were publicized, Biden defended himself from the White House.

"My memory is fine," Biden said. But then he mistakenly called the president of Egypt, Abdel Fattah el-Sisi, the "president of Mexico" while discussing the Israeli-Gaza war.

Concerns over his age were hardly put to bed.

However, such "occasional gaffes" do not indicate anything about an older person's competence, said John Walsh, an associate professor of gerontology at the University of Southern California.

"Fluid intelligence" slows with aging, Walsh said. That means people's reaction times might not be as fast as when they were young, or they might need more time to remember a particular name or date, he said. That knowledge hasn't been lost, though.

Aging experts also refer to this as "benign forgetfulness," and say it's a normal part of the aging process.

"Given more time, they perform at the same level as their younger counterparts," Walsh said.

In fact, the hardest thing for people to remember as they get older are names, Selkoe said.

"But that does not mean there are other aspects of their cognitive function that aren't quite strong," he said.

People in highly stressful and emotional jobs are especially likely to forget certain details, Selkoe said.

"I've seen some very famous politicians in my clinic," he said. "Those people are under a lot of pressure and would have more difficulty in quickly coming up with what is otherwise rather minor information."

The special counsel interviewed Biden right after the Oct. 7 terrorist attack on Israel.

Ageism, or the discrimination of someone based on their age, may lead people to pay outsized attention to Biden's missteps, Walsh said. Nearly 80% of older workers say they've seen or experienced age discrimination in the workplace, according to research by AARP.

"People fear aging," Walsh said. "And we do not like the way aging looks and jump to conclusions that we all age the same, in a bad way."

The research tells a different story.

Age and job performance are largely unrelated

At the UCSF Memory and Aging Center, Kramer said he sees lots of people who are still fully mentally and physically competent in their 80s and 90s.

"Many of them still work," Kramer said. "What is striking is the variability: There are always people in their 80s who are doing better than people in their 50s."

Age and job performance are largely unrelated, said Philip Taylor, a professor at the University of Warwick who studies the aging workforce

"There are areas where older workers outperform younger workers," Taylor said.

Employees later in their careers tend to be more engaged with the well-being of their organization and are likelier to arrive to work on time, he said. Some studies also show that people's vocabularies increase with age and that creativity doesn't wane.

"Think about artists who remain creative at very late ages," Taylor said. (The painter Alex Katz is still working in his late 90s, and Toni Morrison published her last novel at 84.)

"The idea that your most creative years are behind you when you enter your 50s?" Taylor said. "It is not so."

"Crystallized intelligence," considered wisdom, also grows throughout our life, experts say.

"With that wisdom and experience, the older person may be able to sort through possible solutions and come up with an effective strategy for dealing with a situation faster and more successfully than a younger person," Walsh said.

Selkoe seconded that.

"People do get better cognitive function in some areas," he said. "More in their emotional intelligence, [they're] less likely to be bent out of shape by various events because they've experienced them all over decades."

However, Taylor was reluctant of framing any age group as better than another. Ageism hurts younger people too, he said.

"Age is just a really poor proxy for performance at work," he said. "When people ask me about these things, I tell them if you want to make a decision about who to hire, don't make it based on their age."

In Biden's State of the Union address on Thursday evening, the president said that at the beginning of his career — he became a senator at 29 — he was told that he was "too young."

"By the way, they didn't let me on the Senate elevator for votes sometimes," Biden said.

Taylor, who has studied older workers for decades, said he found it depressing that the debate in the U.S. focused so much on Biden's age, with discriminatory words like "elderly" and "senile" being tossed around.

"I think it's a time for celebration," Taylor said. "I've seen older people talking themselves out of working. They say, 'It's too late for me. No one will hire me.' What the president is telling people is, 'I can keep contributing to society.'"

This article was written with the support of a journalism fellowship from The Gerontological Society of America, The Journalists Network on Generations and the The Silver Century Foundation.