WASHINGTON – Presidential candidate and Sen. Bernie Sanders said Wednesday that it's "nonsense" to think his campaign was trying to hide the fact he had a heart attack last week.

During his first sit-down interview since leaving a Nevada hospital Friday, Sanders swatted back claims that his campaign was concealing the medical issue.

"That's nonsense," he told NBC News. "I don't know what people think campaigns are, you know we're dealing with all kinds of doctors and we wanted to have a sense of what the hell was going on really."

Sanders said he believes his campaign "acted absolutely appropriately."

"The first thing that we're trying to do is understand what's going on and not run to the New York Times and have to report every 15 minutes," he said. "You know, this is not a baseball game. So I think we acted absolutely appropriately."

Sanders' campaign last Wednesday announced that doctors found the Vermont Senator had blockage in one artery and two stents were inserted after he felt chest discomfort during a campaign event in Las Vegas.

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It wasn't until Friday that Sanders' campaign officially noted he'd had a heart attack. Arturo E. Marchand Jr. and Arun Guraraj, Sanders' treating physicians, said in a statement that the senator was “diagnosed with a myocardial infarction” at another facility before being transferred to Desert Springs Hospital Medical Center. A myocardial infarction is the medical term for a heart attack.

Sanders at 78 years old is the oldest person running for president in 2020. Former Vice President Joe Biden is 76 and President Donald Trump is 73. Sen. Elizabeth Warren is 71.

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According to NBC News, Sanders also said he "misspoke" when he said Tuesday that he would "change the nature" of his campaign post-heart attack.

"I misspoke the other day, I said a word I should not have said and media drives me a little bit nuts to make a big deal about it," Sanders said. "We're going to get back into the groove of a very vigorous campaign, I love doing rallies and I love doing town meetings.”

Contributing: Savannah Behrmann