Hillary Clinton's health has taken center stage in the presidential election after the Democratic nominee appeared frail and nearly collapsed during a 9/11 memorial in New York City on Sunday.

Her campaign announced that she was "overheated," and her physician claimed that she was diagnosed with pneumonia on Friday. But, those explanations don't add up.

Over the last few years Clinton has dealt with a some health issues, from an elbow fracture in 2009, a fall and concussion in 2012, and a blood clot in 2013. While none of these incidents seemed serious, rumors have circulated for some time that there was something else going on with the former Secretary of State.

Clinton's health became the topic of conversation again back in the winter of 2016 when she began to have public coughing fits. She'd go on for minutes with a deep phlegmy cough, and was even seen spitting phlegm into a glass of water during a speech.

The campaign tried to explain this away and claimed she had seasonal allergies, which caused her to have coughing fits.

As a fellow sufferer from allergies, I can attest that the pollen was especially bad in New York City this year and left many people feeling under the weather. Nonetheless, allergy season ended months ago, but Clinton's cough remained.

In fact, Clinton experienced public coughing fits all the way back in January when she was campaigning in Iowa, when the pollen count would have been low. The Democratic nominee's cough only seemed to worsen after the spring allergy season ended, with noticeable incidents occurring in June, August, and early September.

Undoubtably, Clinton's fainting spell during the 9/11 memorial was the worst episode yet. She seemed unstable, her knees buckled, and she was held up by secret service.

Hillary Clinton 9/11 NYC pic.twitter.com/q9YnsjTxss — Zdenek Gazda (@zgazda66) September 11, 2016

Her campaign and her physician have issued contradicting statements about her health. Nick Merrill, the campaign spokesman, released a statement that said Clinton was just a little overheated at the memorial, which was held on a cloudy, 75 degree day.

Clinton's team said the Democratic nominee left to recover at daughter Chelsea's apartment, resting and playing with her grandchildren, who are one and three months old.

She emerged from her daughter's apartment much better and even took a photo with a young girl.

Hours later however, Clinton's physician, Dr. Lisa Bardack M.D., announced that the former first lady was diagnosed with pneumonia on Friday and put on antibiotics. The Democratic nominee canceled a series of events in California including an appearance on The Ellen Show.

If Clinton is suffering from pneumonia, why would she go to play with her grandchildren and even embrace a young girl on the street for a photo?

Her personal actions, campaign statements, and doctor's notes are not compatible and Clinton should be examined by an independent physician and release her medical records. Until then voters can only guess that the Clinton's are lying about the state of her health.