Hillary Clinton and Donald Trump (AFP/Getty Images)

Hillary Clinton's health is front and center in the 2016 presidential campaign after she grew "overheated" during a visit to a Sept. 11, 2001, memorial service Sunday — a condition later explained by Clinton's personal doctor as a direct result of a case of pneumonia, which she had been suffering from since at least Friday.

Clinton's health scare comes after months of chatter in conservative circles about whether the Democratic nominee is hiding some broader and more serious illness, based in large part on Clinton's coughing fits, the most recent of which came at a campaign event on Labor Day.

It also comes in the same week Donald Trump is scheduled to appear on "The Dr. Oz Show" to talk about his overall health.

There's lots and lots of spin and speculation out there about the relative wellness of Clinton and Trump, in no small part because of the fact that at ages 70 (Trump) and 68 (Clinton), they are the two oldest nominees for president in modern history, and because of the unfortunate reality that neither has been particularly forthcoming about their medical pasts.

Here's my best attempt to cut through all of these theories and conjecture. This is exactly what we know about the overall health of the two candidates for president.

Hillary Clinton

Let's start from Sunday and work backward.

On Sunday morning, Clinton grew "overheated," according to her doctor, Lisa Bardack. Video of Clinton leaving the 9/11 memorial event in New York shows her wobbly and unsteady on her feet. Bardack said in a statement Sunday afternoon that Clinton had been diagnosed with pneumonia Friday and her unsteadiness was a direct result of that illness.

Here's Bardack's full statement:

Six days prior, at a Labor Day rally in Cleveland, a fit of coughing forced Clinton to stop speaking at the start of her address.

Clinton has been bothered by these coughing attacks periodically on the campaign trail, usually ascribing them to "allergies."

That's broadly consistent with a letter from Bardack that was released in late July 2015 detailing Clinton's overall health. Bardack wrote that Clinton was a "healthy 67 year old woman" who suffered at the time from "hypothyroidism" and "seasonal pollen allergies."

The bulk of Bardack's letter is dedicated to Clinton's fall in late 2012 that led to a concussion and a blood clot. Here's the relevant part of her description of those events:

(Bill Clinton, not a doctor, said it took his wife six months of "serious work" to recover from that fall.)

Aside from that incident, Bardack notes that Clinton suffered deep vein thromboses in 1998 and 2009 and broke her elbow in 2009. Clinton had surgery to repair that broken right elbow, injured when she slipped on the way to a meeting at the White House.

Clinton campaign spokesman Brian Fallon said Monday in an interview with NBC's Andrea Mitchell that more medical records will be released soon "to further put to rest any lingering concerns about what we saw yesterday.”

Donald Trump

The entirety of what we know about Trump's medical history comes courtesy of this letter by physician Harold Bornstein released late last year:

According to Bornstein, the Republican nominee has never had any major — or even minor — medical issues. Trump had his appendix out at age 10, but that's about it. "His physical strength and stamina are extraordinary," Bornstein wrote, adding: "If elected, Mr. Trump, I can state unequivocally, will be the healthiest individual ever elected to the presidency." (The story behind how Bornstein came to write the letter is baffling and fascinating.)

Trump promised Monday morning during an appearance on "Fox and Friends" that he will be releasing "very, very specific" results of a recent physical sometime in the near future. “I think they’re going to be good," he said. "I feel great.”

The most likely time for Trump to release those results will be Thursday, when he appears on "The Dr. Oz Show," hosted by physician Mehmet Oz. On the "Today" show Monday, Oz told Savannah Guthrie only that Trump would be appearing on the show.