New York Times reporter Michael Schmidt reported in his new book Donald Trump vs. the United States that Trump took a non-scheduled visit to Walter Reed National Military Medical Center last November that resulted in vice president Mike Pence being told he might have to temporarily take over the duties as president in the event that Trump had to be anesthetized. That worst case scenario never happened, but the mystery of as to what caused Trump’s non-scheduled visit remains. 

Joe Lockhart of CNN has floated the theory that Trump had a stroke and Trump has since denied that that theory rather vehemently. In a race where age is such a prominent issue, either candidate suffering a major medical problem could have a real impact on this race. It’ll be interesting to see if more comes out on what happened to Trump last November and whether or not health/age becomes even more of a factor in this election. 

Trump goes after Drudge over rumors of 'mini-strokes'The president's campaign also called for CNN to fire Joe Lockhart, saying he had spread the story.www.politico.com

This seems like the type of thing the Republicans would say about Biden or Hilary or whomever. It makes me feel uncomfortable that the Democrats would start using these techniques to fight against the Trump even if the Republicans didn’t play fair. Of course it could be true but it still makes me feel uncomfortable about even saying it. It would be nice if Democrats could win this while taking the high road.

Totally agree. It's also bad journalistic practice to throw out a rumor like this without having any inside knowledge.