Democrat presidential candidate Joe Biden said on Tuesday that it is important that whoever he selects to be his vice president, assuming he secures his party’s nomination, is able to be president because he is “an old guy.”

“I can think of at least eight women, at least four or five people of color, that I think are totally qualified to be vice president of the United States,” Biden said. “But for me, it has to be demonstrated that whoever I pick is two things.”

“One, is capable of being president, because I’m an old guy,” Biden said as the crowd laughed. “No, I’m serious. Look, thank God I’m in great health, I work out, no I’m serious, you know I work out every morning. I’m in good shape.”

WATCH:

.@JoeBiden: "Whomever I pick” for VP, must “be capable of being president, because I’m an old guy — no I’m serious!” pic.twitter.com/WGnGkNnghI — Tom Elliott (@tomselliott) January 29, 2020

With his remarks, Biden played right into President Donald Trump’s nickname for him, “Sleepy Joe Biden,” suggesting the “very slow” and “exhausted” candidate is running out of energy.

A review of Trump’s Twitter account shows that Trump has referred to Biden using the nickname dozens of times.

Here are a few examples: