Biden and Trump both claim they are young as the septuagenarians spar in 2020 race

‘I think that I just feel like a young man. I’m so young. I can’t believe it, I’m the youngest person’

President Donald Trump speaks to reporters before boarding Air Force One at Joint Base Andrews, Maryland, on Friday (Reuters)

Donald Trump is 72, and he says he is the “youngest person”. Joe Biden is 76, meanwhile, and he says he must look younger than the president.

The two septuagenarians are both decades older than the youngest candidate in the 2020 race, but both are focusing on their physical fitness just a day after Mr Biden formally announced his candidacy.

The ageist volleys were started by Mr Trump, who implied that Mr Biden is a benign grandfather who might fall asleep in an armchair by calling him “sleepy Joe” on Twitter. Then, the president marvelled about how good he feels on the White House lawn on Friday.

“I think that I just feel like a young man,” Mr Trump told reporters. “I’m so young. I can’t believe it, I’m the youngest person.”

Then, commenting on the ages of Mr Biden and Bernie Sanders – 77 – the president suggested the Democratic front-runners make him look good.

“They are all making me look young both in terms of age and, I think, in terms of energy,” Mr Trump told the reporters, most of whom are considerably younger than the president. “I think you people know that better than anybody.”

Mr Biden responded soon after during an interview on ABC’s The View.

“If he looks young and vibrant compared to me, I should probably go home. Everybody knows who Donald Trump is,” Mr Biden said. “The best way to judge me is watch. See if I have the energy and capacity. This is a show-me business.”

Mr Sanders has so far not weighed in on the ongoing quarrel between Mr Biden and Mr Trump.