WASHINGTON — The nation is poised to elect one of its oldest presidents, and while age doesn’t determine health, it begs the question: How much do we know – and should we know – about how physically fit Donald Trump and Hillary Clinton are for the job?

“Age always matters” when it comes to risk for disease, said well-known aging researcher S. Jay Olshansky of the University of Illinois at Chicago, but he cautions that it shouldn’t be a litmus test for the presidency.

Trump at 70 would be months older than Ronald Reagan on his Election Day, and Clinton will have just turned 69.

Age aside, releasing at least some medical information is an election-season ritual.

Clinton has revealed more of this usually intensely private data than Trump. Each had their own doctor write a letter last year attesting they’re in excellent health. Clinton’s was nearly two pages and included standard lab test results. Trump’s was four paragraphs with few details.

That’s a far cry from 2008, when Republican Sen. John McCain, then 71, released more than 1,000 pages of medical records to show he was cancer-free and fit to serve as president.

The letter approach isn’t enough for some experts, who say an independent panel should assess would-be presidents’ health, like the fit-for-flight physicals pilots take. History shows presidents have been adept at hiding frailty: Woodrow Wilson’s secret stroke; Franklin D. Roosevelt’s severe heart disease during his final campaign; Grover Cleveland even sneaked onto a boat for cancer surgery.

“What have we done to help independently vet those who would lead the most powerful nation on earth? Nothing,” bioethicists Arthur Caplan of New York University Langone Medical Center and Jonathan Moreno of the University of Pennsylvania wrote in the Chicago Tribune.

The travel, junk food, crowds and questions that are part of campaigns make for “an incredible cardiovascular stress test,” said Dr. Michael Roizen, chairman of the Cleveland Clinic’s wellness institute.

But over potentially eight years in the White House, “you want them to have mental functioning that is both quick and intact,” Roizen said.