Hillary Clinton has cancelled a trip to California to attend fundraising events after it emerged the Democratic presidential nominee has pneumonia and been advised to rest by her doctor.

An aide announced the cancellation on Sunday night following Clinton’s abrupt departure from the 9/11 memorial ceremony in downtown Manhattan because, her campaign initially said, she felt “overheated”.

Clinton was scheduled to attend fundraisers on Monday and Tuesday in California, and tape an episode of the Ellen DeGeneres Show.

On Sunday morning Clinton was helped into a car away from the memorial, where she had been attending a ceremony marking the 15th anniversary of the September 11 attacks. She later travelled to her daughter’s apartment, and eventually to her home in Chappaqua, New York, before her campaign gave a more complete explanation of what had happened.

“Secretary Clinton has been experiencing a cough related to allergies,” Dr Lisa R Bardack said in a statement. “On Friday, during follow up evaluation of her prolonged cough, she was diagnosed with pneumonia. She was put on antibiotics, and advised to rest and modify her schedule.

“While at this morning’s event, she became overheated and dehydrated. I have just examined her and she is now rehydrated and recovering nicely.”

Clinton left the Ground Zero ceremony after an hour and 30 minutes. Video posted by a bystander to Twitter appeared to show the former secretary of state extremely unsteady and supported by aides, being helped from the curb into a vehicle.

A security official who did not wish to be identified told the Guardian Clinton had walked from the ceremony without support, got into a vehicle and been driven away.

“She didn’t look great,” he said. “Maybe she was dehydrated. These guys work 16 hours every day.”

A statement from her campaign spokesman, Nick Merrill, subsequently said: “Secretary Clinton attended the September 11th Commemoration Ceremony for just an hour and 30 minutes this morning to pay her respects and greet some of the families of the fallen.”

Later versions of the statement omitted the word “just”.

Merrill added: “During the ceremony, she felt overheated so departed to go to her daughter’s apartment, and is feeling much better.”

Clinton’s van and security detail travelled to Chelsea Clinton’s Manhattan apartment, in the Flatiron at 26th and Madison Avenue.



Hillary Clinton departs the 9/11 memorial. Photograph: Andrew Harnik/AP

Reporters travelling with the campaign noticed Clinton’s departure from the memorial at about 9.36am. The campaign did not respond to their questions or those from the Guardian until 11.03am local time, an unusually long lapse from a meticulous campaign organisation. The campaign later said Clinton had not intended to stay for the entire ceremony at Ground Zero, where temperatures were in the low 80s fahrenheit, about 28C, with relatively low humidity of around 46%.

Clinton left her daughter’s apartment at about 11.45am, smiling and waving to a scrum of cameras and posing for a picture with a young girl before stepping into a campaign vehicle.

“I’m feeling great. It’s a beautiful day in New York,” she said, before heading for her home in Chappaqua, in New York state. According to the Clinton campaign, Dr Bardack examined Clinton there.

Clinton, who spoke at a fundraising event in New York on Friday night, recently sustained a coughing attack during a campaign event in Cleveland, fuelling rightwing suspicion about her health and leading to the creation of a hashtag, #HackingHillary. Her opponent, Donald Trump, used reaction on social media to push his case that the press is biased, tweeting: “Mainstream media never covered Hillary’s massive ‘hacking’ or coughing attack, yet it is #1 trending. What’s up?”

Despite a lack of evidence that Clinton is in poor health, Trump and his allies have insinuated that her health is declining and she “lacks the stamina” to be commander-in-chief at the age of 68. Clinton’s campaign has accused her 70-year-old opponent of peddling conspiracy theories.

Clinton has made light of such speculation, joking to talkshow host Jimmy Kimmel: “Back in October, the National Enquirer said I’d be dead in six months. So with every breath I take, I feel like it’s a new lease on life.”

Rumors about Clinton’s health appear to stem from a 2012 incident in which Clinton fell, a mishap attributed to a stomach virus. She suffered a concussion and a subsequent blood clot in the brain, which later testing showed to have cleared completely.

Dr Bardack is chair of internal medicine at the Mount Kisco Medical Group in New York and has been Clinton’s personal physician since 2001. She addressed Clinton’s concussion in 2012, for which the Democratic nominee still takes an anticoagulant. In a doctor’s note released last summer, Bardack declared Clinton “in excellent physical condition and fit to serve as president of the United States”.

In 2008, Barack Obama, then 47, released a 276-word report about his health. His opponent, John McCain, then 71, made available more than 1,000 pages related to his own medical history.



In contrast, Clinton has released only a few pages of records and Trump has released only a letter from his personal physician which contains few details and which the doctor subsequently said was “rushed”, prompting calls for more detail from both candidates.

Trump is scheduled to appear on the Dr Oz television show later this week, to discuss both presidential nominees’ health.

A spokesman for Gary Johnson, the Libertarian nominee, said in a statement to the Guardian on Sunday: “Given Governor Johnson’s level of fitness and exercise, his medical records haven’t been much of an issue. We will discuss with him how and what information to release.”