Democratic vice presidential nominee Tim Kaine tells supporters in Dayton, Ohio, that despite her recent pneumonia diagnosis, Hillary Clinton is in good spirits. Clinton fell ill at a Sept. 11 memorial, an episode that renewed focus on her health less than two months before the election. (Reuters)

DAYTON, Ohio — Tim Kaine, the running mate of Democratic presidential nominee Hillary Clinton, declined to say Monday when he first learned of Clinton’s pneumonia diagnosis but said that the pair had not talked about her health for nearly a week prior to Sunday’s commemoration of the Sept. 11, 2001, terrorist attacks in New York.

Kaine, who was campaigning in the swing state of Ohio, said at a rally here that he emailed Clinton shortly after learning of her abrupt departure from the ceremony due to what an aide later described as feeling overheated.

“I can tell you this,” Kaine said. “Within a few minutes after I heard the news, I had reached out to communicate to her and she reached right back out to me and said, ‘I’m going to be fine.’ And then she started making fun of me because I was sitting reading endless debate prep memos.”

Kaine, a senator from Virginia, added that he continues to be impressed by Clinton’s stamina.

“Her energy staggers me,” he said. “I have a hard time keeping up with her.”

Fielding questions from reporters afterward, Kaine would not say when he first heard Clinton has pneumonia. The diagnosis — which her doctor said was made Friday — was disclosed Sunday, several hours after Clinton’s stumbling departure from the event in New York.

“The first time I talked to Hillary about this was Sunday, so I’ll just say it like that,” Kaine said. “I don’t want to get into the character of communications. But I reached out to her as soon as the incident happened on Sunday, and we had a good dialogue there.”

Asked whether he had learned about the diagnosis prior to Sunday, Kaine said the last time the two discussed Clinton’s health was at an event they both attended in Cleveland on Labor Day. At that event, Clinton had a prolonged coughing fit at the outset of her remarks.

“I obviously knew from Monday, when she was coughing, that she had a cough, and it was likely an allergy,” Kaine said. “The first time we talked after we were together Monday was — I reached out to her after yesterday in New York.”

Kaine said that he and Clinton have "a warm and friendly and communicative relationship” but that they don’t speak every day.

“Anytime I need to talk to her, I do, and we talk immediately, and sometimes it’s one-on-one and sometimes it’s part of a larger group," he said.

Kaine said he had a similar episode with pneumonia when he was running for the Richmond City Council in 1994.

“I lived through something very similar in my first race, and I kind of know what [Clinton's] thinking was, which was, ‘Okay, I’ve got a diagnosis. It’s serious, but it’s something that a lot of people manage.’ ”