Politicians are getting older.

This month, 92-year-old Mahathir Mohamad was sworn in as Malaysia’s new prime minister, making him the oldest elected leader in the world. In the United States, President Donald J. Trump is 71, the oldest first-term president elected the country’s history. U.S. Sen. Bernie Sanders, who ran for president in 2016 and announced on Monday his intention to run for re-election to the senate this fall, is 76.

While these leaders are long on experience—Mohamad previously led Malaysia for 22 years, Trump is a storied real estate baron, and Sanders has spent the past 28 years in the senate—how can we trust that the natural decline in cognitive function over time won’t affect their ability to lead?

“A resilience to aging is pretty impressive,” said Ambika Bajpayee, assistant professor of bioengineering who is affiliated with Northeastern’s Global Resilience Institute. “That’s what’s enabling us to put our hopes and trust in aging people and let them lead.”

Her assessment was echoed by Holly Jimison, professor of the practice and another GRI-affiliated faculty member. She suggested that elected officials’ political ambitions and drive might make them more resistant to the loss of mental capacity that naturally comes with age.

There’s quite a bit that can be done to keep older adults functional in order to take advantage of the wisdom they’ve acquired over the years. We’ve lost a valuable resource if people withdraw from the public sphere just because they’re older.

Holly Jimison,P rofessor of the Practice, College of Computer and Information Science and Bouvé College of Health Sciences

“People in politics are clearly driven by something much bigger than them that’s going to make them more functional in older age than others,” said Jimison. “Energy is a predictor of cognitive ability.”

In an interview with The Associated Press in April, Mohamad insisted he’s fit to lead.

“I am, of course, quite old. No, I am very old. But I can still function,” he told reporters in Kuala Lumpur. “Young leaders do not have sufficient background,” he said in the interview. “And not many people with experience have survived. I have survived.”

It’s not just politics that energize people. The sort of passion Jimison pointed out can be found across career fields.

“We’re seeing older adults in the political scenario right now, but look at any other sector,” Bajpayee said.  “In academia, there are very old professors who are very mentally sound, in business you see people in their late 70s making major decisions. It has to do with passion, and that’s an innate thing.”

Plus, advances in technology have enabled people not only to live longer, but to have more productive years toward the end of their lives–something that helps compensate for what passion alone may not always solve.

“With dedicated health interventions, there are ways to help people extend their capabilities,” Jimison said.

Those interventions include things like memory and cognition games,which Jimison and her team of researchers are developing, as well as monitoring and managing personal stress, and creating opportunities for social events.

“There’s quite a bit that can be done to keep older adults functional in order to take advantage of the wisdom they’ve acquired over the years,” Jimison said. “We’ve lost a valuable resource if people withdraw from the public sphere just because they’re older.”

Jimison and Bajpayee are two of a growing number of researchers studying the science of aging, a field which Bajpayee said is focused on not just extending human lifespan, but extending the number of healthy years people have.

Leaders like Mohamad, Trump, and Sanders may be reaping the benefits of such research.