Now, Clinton's campaign has released a new doctor's letter that provides an overview of her health records
, which reveal that her health has somewhat remained stable since her records were divulged last year.
"We have a little bit more detail about this most recent episode with pneumonia. We understand now that she had some symptoms for some time," said Dr. Sanjay Gupta, CNN's chief medical correspondent and a practicing neurosurgeon.
"When I look at these types of letters, I'm looking for things that are big. Is there any underlying illness?" Gupta said of the letter. "I wouldn't say that there's anything that's abnormal in here."
The Democratic presidential nominee left the commemoration ceremony early, after an hour and a half, when she started to feel "overheated," campaign spokesman Nick Merrill said in a statement. She took some time to recover, about an hour and 45 minutes, at her daughter's apartment. When she re-emerged about noon, she waved to passers-by
and told reporters she was feeling "great."
The incident occurred just days after Republicans argued that moments when Clinton coughed along the campaign trail
were signs of a more serious health issue. Her campaign said she suffered from seasonal allergies.
"My overall impression is that Mrs. Clinton has remained healthy and has not developed new medical conditions this year other than a sinus and ear infection and her recently diagnosed pneumonia. She is recovering well with antibiotics and rest. She continues to remain healthy and fit to serve as President of the United States," Clinton's physician, Dr. Lisa Bardack, said in the new letter.
From seasonal pollen allergies to hypothyroidism
, here's what we know about the 68-year-old presidential candidate's health.
Clinton's blood clots
Clinton's current bout with pneumonia does not negate the fact that as secretary of state, she withstood an extensive travel schedule and maintained good health.
In a report that was released in July 2015
(PDF), Bardack wrote, "Mrs. Clinton is a healthy 67-year-old female whose current medical conditions include hypothyroidism and seasonal pollen allergies. Her past medical history is notable for a deep vein thrombosis in 1998 and in 2009, an elbow fracture in 2009 and a concussion in 2012. ..."
"She participates in a healthy lifestyle and has had a full medical evaluation, which reveals no evidence of additional medical issues or cardiovascular disease. Her cancer screening evaluations are all negative. She is in excellent physical condition and fit to serve as President of the United States."
Clinton was advised in 1998 to take blood-thinning medications to prevent deep vein thrombosis blood clots when she traveled on long-distance flights, Bardack wrote.
Blood clots can be a serious health risk for travelers
, according to the United States Centers for Disease Control and Prevention. They can form in the deep veins of the legs when a person sits still for an extended period, such as during long flights. The problem turns serious if the blood clot breaks off and travels to other parts of the body, such as the lungs.
Along with taking blood-thinning medication, Clinton takes medication for hypothyroidism
, a condition in which her thyroid gland is underactive and doesn't produce enough important hormones, according to Bardack's report.
The report also indicated that, in a physical exam on March 21, 2015, Clinton's vital signs appeared "healthy," with a blood pressure of 100/65, heart rate of 72, respiratory rate of 18 and temperature of 98.7. The remainder of her exam was normal.
In the new letter, Clinton's vital signs showed blood pressure of 100/70, heart rate of 70, respiratory rate of 18, temperature of 97.8 and pulse-oximetry of 99%.
Clinton's bones and brain
Clinton's health history also includes a bone fracture. She stumbled at the State Department in summer 2009 and fractured her right elbow
. The injury resulted in her having to undergo a two-hour surgery
, which was deemed successful.
Then, in December 2012, Clinton suffered a stomach virus after traveling and fainted, which caused her to suffer a concussion, according to Bardack's report. In follow-up evaluations, she was found to have a transverse sinus venous thrombosis
-- in other words, a blood clot in the brain. The clot later dissolved.
A concussion is a brain injury, explained Gupta.
"What we've heard from her medical note is, looking at the follow-up, there would be some concern, but she's been tested, and there's no long-term impact from her brain, and the blood clot has resolved," he said.
Gupta added that it is difficult to comment on Clinton's health without additional information.
"This diagnosis of pneumonia came in on Friday," he said. "It's a totally treatable thing, there's no question about it, but it's a serious diagnosis still and is something that should not be taken lightly."
The Donald Trump campaign hadn't commented on Clinton's pneumonia diagnosis as of Sunday evening. Trump himself has released minimal information about his health.
Dr. Harold Bornstein, Trump's personal physician, released a letter
(PDF) in December that lacked much medical detail but noted that Trump would be "the healthiest individual ever elected to the presidency."
Gupta found such language in the letter to be surprising
and "almost comically" lacking objectivity.