When Donald Trump took office on January 20, 2017, no previously elected president had ever been as old — at least not on his first inauguration day, as Forbes shows. Trump was 70 years old at that time, and is now 72. Previously, Ronald Reagan — aged 69 on his first inauguration day of January 20, 1981 — was the oldest elected president.

But a day after former United States Vice President Joe Biden declared his presidential candidacy in a video posted to YouTube, Trump ridiculed Biden’s age in a brief exchange with reporters — and boasted of his own supposed youth.

“I just feel like a young man. I’m so young. I can’t believe it,” Trump said, as quote by The Associated Press. “I’m a young vibrant man.”

Trump then took a jab at Biden, saying, “I look at Joe. I don’t know about him.”

He also took a swipe at the entire Democratic field, claiming that the candidates in that race are “making me look young, both in terms of age and energy,” according to TPM. Trump also referred to himself as “the youngest person.”

The latest Real Clear Politics polling average shows the 76-year-old Biden currently leading the Democratic field, followed by 77-year-old Vermont Senator Bernie Sanders.

Former Vice President Joe Biden was first elected to the Senate in 1972. Featured image credit: Scott Eisen Getty Images

But third-place candidate Kamala Harris, a California senator, is 54, while fourth-place contender Pete Buttigieg — the mayor of South Bend, Indiana — is only 37, meaning that were Buttigieg to win the presidency, he would be 39 when inaugurated. That would make him four years younger when he took office than the youngest president ever elected, John F. Kennedy, who was inaugurated in 1961 at age 43.

Trump’s claim to display more “energy” than any of the Democratic candidates is also debatable. According to an NBC News report earlier this year, Trump’s personal daily schedule shows that he consumes less than half of each day with scheduled work. On the other hand, about 60 percent of Trump’s typical work day is set aside for “executive time,” which is believed to largely consist of time spent watching television and posting on Twitter.

Trump also takes an extraordinary number of vacation days. According to a separate NBC News report, of his first 826 days in office — that is, through April 19 — Trump had spent 183 days, or more than 22 percent of his term so far, on golf courses that he owns.

He had also spent 98 days at his own Mar-a-Lago resort in Palm Beach, Florida — his destination on many weekends, according to the NBC report.

Biden responded to Trump’s jibe in an interview on Friday morning, saying, “If he looks young and vibrant compared to me, I should probably go home,” as quoted by NBC News. “The best way to judge me is to watch, see if I have the energy and capacity. It’s a show-me business.”