How much should presidential candidates tell the public about their health?
Hillary Clinton, 68, was recently diagnosed with pneumonia, and the public didn't know about it until two days later, when she abruptly left a Sept. 11 memorial ceremony feeling unwell and needing to be helped into a vehicle.
If Donald Trump, 70, were elected, he would be older than any previous president at the start of his first term — and, like Clinton, he hasn't released detailed records about his health beyond a doctor's letter. Both candidates promised Monday to release more detailed medical records soon.
But the idea of presidential candidates, or sitting presidents, disclosing their health history is relatively new. And though recent presidents have released detailed updates about their health, there is no law mandating disclosure.
America has a rich history of presidents and presidential candidates hiding their health problems from the public, sometimes successfully and sometimes with serious consequences.
What have recent presidential health disclosures looked like?
The report for President Obama's most recent physical examination, in February, by White House physician Ronny L. Jackson is two pages long.
It lists basic vital information such as his height, weight, body mass, resting heart rate and blood pressure, as well as numbers from laboratory tests for his cholesterol, glucose and vitamin D levels, among other information.
The report also lists the results of tests for Obama's physical and neural health, lists the medication he is taking (which includes the occasional use of nicotine gum) and says he drinks alcohol only occasionally.
"All clinical data indicates that the president is currently very healthy and that he will remain so for the duration of his presidency," the report concludes.
A similar report for George W. Bush in 2006 was four pages long and included a lengthy medical history.
What have Trump and Clinton's doctors' letters looked like?
In 2015, Clinton released a two-page letter from her doctor that discussed Clinton's medical history, including her hypothyroidism — a type of hormone deficiency — and the concussion she suffered in 2012 after she was weakened by a stomach virus and dehydration.
The letter also disclosed her blood pressure, respiratory rate, cholesterol levels, as well as her exercise habits, which include yoga, swimming and weight training.
"She is in excellent physical condition and fit to serve as president of the United States," wrote Dr. Lisa Bardack, chairwoman of internal medicine at CareMount Medical in Mount Kisco, N.Y., who has been Clinton's physician since 2001.
The letter released by Trump's doctor in December is four paragraphs long, and said Trump had had no significant health problems over the last 39 years.
The letter gives figures for Trump's blood pressure and his prostate blood test, says he takes 81 milligrams of aspirin and a "low dose" of cholesterol-lowering statin daily, and variously describes Trump's health as "astonishingly excellent," "extraordinary" and "excellent."
"If elected, Mr. Trump, I can state unequivocally, will be the healthiest individual ever elected to the presidency," said Harold N. Bornstein, a gastroenterologist at Lenox Hill Hospital in New York who has been Trump's physician since 1980.
Why does it matter?
Nearly half the presidents in the nation's history have had significant illnesses or injuries while in office, including most of the presidents since the start of the 20th century, according to academic research on presidential health. Many of those presidents hid their health problems from the public.
Grover Cleveland had a secret surgery for oral cancer during his second term in 1893, survived and served until 1897, and his surgery was not revealed to the public until 1917, nine years after his death.
Woodrow Wilson had a serious stroke in 1919 that in effect ended his ability to run the country, yet his condition was kept secret. His wife, Edith, quietly took over his work until his term ended in 1921.
Wilson's successor, Warren Harding, didn't have much better luck: In poor health for years, he died in office in 1923 while traveling in San Francisco. His wife declined to have an autopsy done.
Paralysis caused by polio did not prevent Franklin Roosevelt from taking office and serving with distinction starting in 1933. But by Roosevelt's fourth campaign in 1944, his health was failing. He won and then died of a cerebral hemorrhage in April 1945, leaving Vice President Harry Truman to finish World War II.
Dwight Eisenhower had a well-publicized heart attack during his first term in 1955. Doctors weren't sure whether he would survive a second term, but he ran for reelection the next year, won and lived until 1969.
Among other health problems, his successor, John F. Kennedy, had Addison's disease, an adrenaline deficiency, which his team denied during his 1960 campaign — a lie that may have helped Kennedy win the razor-thin election against Richard Nixon. Kennedy was assassinated in 1963.
Lyndon Johnson, Kennedy's successor, flouted that type of discretion. After Johnson had gall bladder surgery in 1965, he lifted up his shirt to show reporters his scar.
How much should candidates disclose?
Since vice presidential candidate Thomas Eagleton dropped out of the 1972 presidential race after the disclosure that he had been hospitalized for depression, "the health status of presidential candidates has been seen as fair game by the press," George J. Annas wrote in a 1995 article for the New England Journal of Medicine.
Health disclosures by modern presidential candidates, although generally standard since then, are still sometimes an uneven affair. Democratic hopeful Eugene McCarthy refused to release his medical records in 1976, calling them private.
Bill Clinton resisted releasing his health records during his first run in 1992, leading the New York Times' doctor-reporter Lawrence K. Altman to declare that the Democrat had been "less forthcoming about his health than any presidential nominee in the last 20 years."
Clinton continued to resist releasing his full records during his reelection in 1996, which led Republicans to repeatedly raise questions about whether he was hiding a secret health issue. His opponent, Bob Dole, issued detailed medical results and made his doctor available for an interview.
Obama initially released a one-page letter from his doctor in 2008 with no supporting documents, then later released lab tests and echocardiograms. His opponent, John McCain, gave reporters several hours to review 1,200 pages of health records.
The release of health records has not been standardized practice compared with the release of tax records, which is common for candidates (with the notable exception of Trump, who has declined to release his).
Although 96% of respondents in a 2004 Gallup poll said the president's health was "important," 61% of respondents said presidents should have a right to choose to keep their health records private like everyone else.
Without a legal mechanism to force disclosure for such records, "you really need the public to hold them accountable," said Robert Streiffer, associate professor of bioethics and medical history at the University of Wisconsin-Madison.
But the bar for disclosure should be high, Streiffer said. He defined the threshold as "a condition that has a significant chance of seriously undermining the person's ability to perform the core competencies of the presidency if they are elected."
Former White House physician Lawrence C. Mohr said that althought "the American people are entitled to know the health status of their president and presidential candidates ... the release of any medical information has to be the decision of the candidate and not the doctor."
If disclosure happens, Mohr said, "the information should be accurate, it should be complete, it should be timely, and it should include whatever medicine is being prescribed, and the physician should offer some prognosis about how long it will take to get well."
Mohr, who was a White House physician during the Reagan, George H.W. Bush and Clinton administrations, said public understanding was also an important part of disclosure.
"Just because a president has an illness doesn't mean that's a disqualifying factor if that illness can be effectively treated," Mohr said, pointing to Roosevelt's long years in office.
The things that are really important, Mohr said, are not the name of the illness or the specific diagnosis, but whether the president can think clearly, act appropriately and communicate effectively.