(NewsNation) — American voters are worried about age and cognitive function impacting President Joe Biden’s and former President Donald Trump’s ability to effectively serve in office, according to a NewsNation/Decision Desk HQ (DDHQ) poll.

Biden, 80, and Trump, 77, are just three years apart in age, but voters showed more concern for the current president’s faculties.

In the September poll, about 40% of Americans say Biden’s age would strongly inform their vote, while 52% say they’re very concerned about his cognitive health and how it would impact his performance.

They also showed concern about Trump’s age, though to a lesser degree. About 38% said they are very concerned about Trump’s cognitive health. As for Trump, 23% of respondents reported having no concerns about his cognitive health compared to 13% who said the same about Biden.

An NBC News poll released Sunday showed similar findings. Among those respondents, 74% reported major or moderate concerns that Biden doesn’t have the mental and physical capacity to be president, while 44% said the same about Trump.

Media coverage could explain why some are more worried about Biden’s age than Trump, Decision Desk HQ Advisor Scott Tranter said.

“The White House worries about what stairs President Biden goes up and down because they don’t want a falling incident,” Tranter said. “Whereas Donald Trump still goes out and gives 90-minute speeches and shows up to the Iowa State Fair.”

Concern about Biden’s age and ability is greater among Republicans, but a majority of Democrats shared the same opinion, according to the poll.

“I think what’s most telling is it’s not just independents and Republicans worried about Biden’s health and age,” Tranter said. “It’s the Democrats, too.”

The White House isn’t the only office where voters are concerned about age, either. About 71% say they would support an age limit on people in Congress, the NewsNation//DDHQ poll found.

California’s Democratic Gov. Gavin Newsom has come to Biden’s defense. The governor recently tried to shut down concerns about the president’s age, telling NewsNation, “The administration’s record speaks for itself.”

“I’m for performance on the court, and this guy’s producing those results,” Newsom said. “Every single day… 24/7 disciplined and focused.”

It’s the economy, not the president’s age, that ranks chief among voters’ concerns, however. The majority of Americans – 67% – say the country is on the wrong track, with about 47% agreeing the economy is the most important issue they’ll consider when deciding who to vote for in the general election, according to the NewsNation/DDHQ poll results.

Immigration, climate change and abortion followed, in that order.

Republicans were more likely than Democrats to say the country is headed the wrong way. Nearly 87% of Republicans shared that sentiment, compared to 43% of Democrats.

There was a larger disparity between party lines among those who believe the country is on the right track. About 42% of Democrats say it is, compared to 10% of Republicans.

Decision Desk HQ conducted the national poll of 1,000 registered voters between Sept. 19 and 20, with a margin of error of about 3%.

NewsNation digital reporter Zaid Jilani contributed to this report.