Democratic presidential nominee Joe Biden went on the offensive on Sunday in the war of words between him and President Trump over who the fittest man – both mentally and physically – to lead the country.

As the fitness feud between the two septuagenarians heats up as Election Day quickly approaches, Biden asked the American public to take a good look at him and Trump, and decide who’s in better shape.

“When it comes to Donald Trump versus me: Just look at us. Okay? Just look at us,” Biden said during an interview on CNN. “Who seems to be in shape? Who’s able to move around?”

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Biden, who has been nicknamed “sleepy Joe” by Trump, laughed off the president’s derogatory remark and vowed to release any information on his health.

“This idea of slow Joe — anyway,” Biden said. ““Donald Trump, just look at us both, watch us, and determine whether or not you think I’m misleading anyone — not you personally, but the public.”

He added: “I guarantee you I will be totally transparent in terms of my health and all aspects of my health.”

Biden has had to constantly defend himself against attacks over his age and mental fitness from Trump and allies.

In an interview shortly after announcing Sen. Kamala Harris, D-Calif., as his running mate, Biden defended his capabilities after months of Trump deriding him over gaffes and verbal screw-ups while on the campaign trail.

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“Watch me. Mr. President, watch me. Look at us both. Look at us both, what we say, what we do, what we control, what we know, what kind of shape we're in,” Biden said, referring to himself and Harris, during an interview on ABC.

The 77-year-old former vice president did admit that he thinks it is a “legitimate question” to ask anyone over 70 if they are up to the demands of being the president, but said he is more than up to the task.

“I think it's a legitimate question to ask anybody over 70 years old whether or not they're fit and whether they're ready,” he said. “But I just, only thing I can say to the American people, it's a legitimate question to ask anybody. Watch me.”

Biden would be 78 on Inauguration Day, which would make him the oldest president ever elected should he win in November. Trump is 74.