The squabble over Hillary Clinton’s pneumonia underlines the need for full medical disclosure by presidential candidates.

Ms. Clinton is 68 and Donald Trump is 70. That’s not a disqualifying age for someone who seeks the job these days. But the public has a right to know whether they have the stamina and physical fitness to withstand the challenging demands of the office they seek.

Ms. Clinton did wrong by failing to disclose last week that she had been diagnosed with pneumonia — and decided to plow through it, regardless. Secrecy seems to be her default position. In this instance, as in the email controversy, it has damaged her credibility and given her critics a cudgel to wield against her.

Whatever her reasons — “I just didn’t think it was going to be that big a deal,” she told interviewer Anderson Cooper on Monday night — Ms. Clinton must surely realize that public doubts over her trustworthiness undermine her campaign. She should have learned by now that every time she tries to hide something, it seems to backfire.

But let’s also be clear that both Ms. Clinton and Mr. Trump have failed to come clean about their health. If anything, Ms. Clinton has done a better job both in terms of her tax records — which she has released while Mr. Trump is hiding his — and health records.

She has released more medical information from her private physician, Dr. Lisa Bardack, than did Mr. Trump in a relatively short and unconvincing letter from his doctor. That valentine could have been written by Mr. Trump himself, boasting about his “strength and stamina.”

That’s a far cry from the hundreds of pages released by Sen. John McCain in 2008 when he ran for president at age 72. President Ronald Reagan was 74 and equally open with the public when he held a candid discussion with reporters in 1985 about his scare with colon cancer.

And those with really long memories may recall when, in 1955, a spokesman for President Dwight Eisenhower, who had suffered a heart attack, told reporters about Ike’s “successful bowel movement.”

OK, maybe that’s too much information. But clearly the public is better served by candor and transparency than by secrecy and evasiveness, and this year both candidates have failed to be fully open and transparent.

Both campaigns have promised to be more forthcoming about their medical histories, but we have to wonder — as is so often the case — whether Mr. Trump intends to make good on his promise. Constancy has never been his hallmark.

After an initial pledge by the candidate on Sept. 6 to release detailed medical records, campaign manager Kellyanne Conway on Tuesday appeared to take it back: “I don’t know why we need such extensive medical reporting when we all have a right to privacy,” she told an interviewer.

Why, she asks? Because a presidential candidate is not a garden-variety citizen. Mr. Trump and Ms. Clinton are seeking an office that comes with a high level of public scrutiny. In a democracy, the president’s health is not a taboo topic nor a matter of national security.

Voters need to know if the presidential candidates are healthy enough to do the job, and they expect them to be forthcoming. It should be required disclosure for anyone who runs for president. If candidates don’t trust the public with this information, voters should not trust them with the responsibility of the presidency.

— The Miami Herald, Sept. 13, 2016