The Democratic candidate had events planned in North Carolina and Washington as she resumed campaigning after a three-day break prompted by a bout of pneumonia.
Clinton, 68, fell ill during a 9/11 memorial ceremony in New York on Sunday and was forced to leave. She was seen stumbling limp-legged into her vehicle.
It took several hours for her personal physician to disclose she had been diagnosed with pneumonia two days earlier, drawing criticism of her campaign’s lack of transparency.
On Wednesday, Clinton looked to head off further questions about her health, releasing new medical records that purported to show she is fit to serve as president and is recovering from mild pneumonia.
The disclosure came as her Republican rival Donald Trump, 70, released health data of his own during the taping of a nationally televised medical chat show set to air Thursday.
Both candidates, among the oldest ever to run for the White House, were under intense pressure to share more medical information after Clinton fell ill.
Recent opinion polls have shown the gap between them narrowing with less than two months to go before Election Day, and the presidential hopefuls disclosed fresh information in a bid to score points with undecided voters.
In a detailed, two-page “summary update” on Clinton’s health, her personal physician Lisa Bardack wrote that the candidate was bouncing back after a diagnosis of “mild, non-contagious” pneumonia.
She “is recovering well with antibiotics and rest” after being laid low over the weekend, when she suffered from fatigue and a low-grade fever, although her vital signs remained normal, Bardack said.
The nominee “continues to remain healthy and fit to serve as president of the United States,” she wrote, noting she is in “excellent mental condition.”
Clinton spent Wednesday at home in Chappaqua, New York for a third straight day.
News of Trump’s appearance on “The Dr. Oz Show” – though it appeared to reveal little detail – had earlier flooded the US airwaves on Wednesday. This raised pressure on Clinton to share more health data before returning to the trail.
I have it right here
So far Trump had released only four, gushing paragraphs on his health, written by his doctor Harold Bornstein in December 2015.
Following the revelation of Clinton’s pneumonia, Trump vowed soon to release specific numbers from a recent check-up with Bornstein.
Team Trump had raised – then dropped – the possibility of releasing them during an appearance on “Dr Oz”.
But during the recording of the segment Wednesday morning, Trump finally did present its celebrity host with the results, according to a statement on the show’s website.
In a snippet teased on the site, Mehmet Oz – who is also a professor of surgery at Columbia University in New York – is seen asking Trump:
“If your health is as strong as it seems… why not show your medical records?
“Well, I have really no problem in doing it,” Trump responds. “I have it right here. Should I do it? I don’t care.”
The Republican nominee goes on to pull the documents from his pocket, to cheers and applause from the show audience.
A statement from the medical chat show said their hour-long one-one-one interview touched on Trump’s cardiovascular health, family medical history and history of cancer, among other topics.
But the actual details revealed appeared to remain very generic.
According to US media who attended the taping, Oz declared Mr Trump “slightly overweight” at 267 pounds (120 kilos) for roughly six foot two inches (1.88 meters).
Trump continued his barnstorming of key battleground states Wednesday with stops in Michigan and Ohio. On Thursday, he is due to deliver a major economic speech.