Trump visited Walter Reed National Military Medical Centre in Bethesda, Maryland, about a month before the Democratic-controlled House impeached him over his conduct toward Ukraine.
"In reporting for this book, I learned that in the hours leading up to Trump's trip to the hospital, word went out in the West Wing for the Vice-President to be on standby to take over the powers of the presidency temporarily if Trump had to undergo a procedure that would have required him to be anesthetised," Michael Schmidt writes in Donald Trump v. the United States: Inside the Struggle To Stop A President.
"Pence never assumed the powers of the presidency, and the reason for Trump's trip to the doctor remains a mystery," Schmidt says in the book. Schmidt is a New York Times and Pulitzer Prize-winning reporter.
Trump responded today on Twitter to Schmidt's reporting and other speculation about his health, and later had his White House doctor attest to his health.
"It never ends! Now they are trying to say that your favourite President, me, went to Walter Reed Medical Centre, having suffered a series of mini-strokes. Never happened to THIS candidate - FAKE NEWS," Trump tweeted.
Trump, 74, appeared to be responding to Clinton White House veteran Joe Lockhart, who tweeted yesterday about Trump, asking, "Did @realDonaldTrump have a stroke which he is hiding from the American public?"
Dr Sean Conley, Trump's White House doctor, followed up with a statement in which he said Trump has not experienced or been evaluated for a stroke, a mini-stroke or any acute cardiovascular emergency.
"The President remains healthy and I have no concerns about his ability to maintain the rigorous schedule ahead of him," said Conley, who flew with Trump to Wisconsin today. "As stated in my last report, I expect him to remain fit to execute the duties of the presidency."
In June, Conley released a statement saying Trump had completed the physical in April. Along with releasing some findings about the president's health, Conley said there were "no findings of significance or changes" and said Trump "remains healthy."
- AP