The incident, which took place 90-minutes after her arrival at the event, is likely to fuel further speculation about the 68-year-old’s medical history and current health status.
Her personal physician insists Mrs Clinton is “fit to serve as President of the United States”, but her 70-year-old rival Donald Trump has repeatedly questioned her health.
:: Hillary Clinton Falls After Leaving 9/11 Memorial Unwell
He has done so despite being under pressure himself to release detailed information about his own medical history.
Instead, in December, Mr Trump’s doctor wrote a short letter that was made public.
It stated that Mr Trump’s blood pressure and laboratory results “were astonishingly excellent” and that he would be “the healthiest individual ever elected to the presidency”.
Since then, the doctor has told NBC News that he wrote the letter in about five minutes, saying he was “rushed” and “anxious” as a limousine was awaiting him.
Here is a brief history of Mrs Clinton’s health over recent years:
Mrs Clinton suffers from deep vein thrombosis.
Mrs Clinton again suffers from deep vein thrombosis. She also fractures an elbow after slipping and falling on her way to a meeting at the White House.
:: December 2012
Mrs Clinton suffers a stomach virus after travelling. She becomes dehydrated and faints, sustaining a concussion.
As a result she was unable to testify as scheduled before Congressional committees investigating the 2012 attack on the American diplomatic outpost in Benghazi, Libya.
Further medical evaluations find that Mrs Clinton was suffering from a blood clot. She also experienced double vision following her concussion.
Follow-up medical checks reveal the effects of the concussion have been resolved. Mrs Clinton also tests negative for all blood clotting disorders.
:: 28 July 2015
Lisa Bardack, MD, the personal physician for Mrs Clinton since 2001, releases a healthcare statement which reveals her patient to be a “healthy 67-year-old female”.
The statement adds: “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.”
:: 5 September 2016
Mrs Clinton interrupts a campaign speech in Cleveland, Ohio, after suffering a coughing fit.
She laughed off the interruption with the quip: “I’ve been talking so much. Every time I think about Trump, I get allergic.”
Mrs Clinton’s campaign aides attributed the coughing fit to allergies.
:: 11 September 2016
Mrs Clinton leaves a memorial event in Manhattan for the victims of the 9/11 terror attacks early after feeling “overheated”.
She recuperates briefly at her daughter Chelsea’s apartment before emerging to tell a reporter she is “feeling great”.
News Source SkyNews