Democratic vice presidential nominee Tim Kaine said Monday that Hillary Clinton’s energy "staggers" him while discussing her health during a campaign event in Dayton, Ohio.

"So, she was immediately responding back and joking around–I know you’re thinking about her and I am too," Kaine said. "But I’ll tell you this–I’ve just been on the campaign since July 22. Hillary Clinton has been on the campaign trail for 18 months. Her energy staggers me. I have a hard time keeping up with her."

Kaine started his comments by addressing Clinton’s health scare during a 9/11 ceremony on Sunday in New York City, where she nearly fainted and had to be helped into a van. The Clinton campaign revealed hours later that the Democratic nominee had been diagnosed with pneumonia on Friday.

"You're probably just like me, thinking about Hillary now after she was at the outdoor ceremony yesterday and got overheated a little," he said.

Kaine then told the audience that when he heard what happened, he reached out to his running mate. He said that she immediately responded and started to poke fun at the fact that Kaine was reading a lot of memos.

"I can tell you this, 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, ‘No, I'm going to be fine,’" he said. "And then she started to make fun of me because I was sitting, reading endless debate prep memos and she said, ‘You know, our staff knows how to kill a lot of trees by putting together massive books.’"

The Clinton campaign has kept to the story that she was just overheated and bounced back almost instantly once she entered an air-conditioned space.

They have also said there are no more undisclosed health issues concerning Clinton.