Some White House staffers say President Joe Biden doesn't realize how old he can come across to others, Axios reported.
Biden likes to tell friends and family, "I feel so much younger than my age."
A former official, however, told Axios: "His age is clearly something voters are worried about, fairly or not, and yelling, 'Nuh-uh' isn't cutting it."
With polls showing that more than 70% of voters have concerns about Biden, 81, serving a second term, his reluctance to acknowledge his physical limitations is causing tension on his team, Axios reported Tuesday.
Current and former aides to Biden say he often pushes to do more travel and events than they recommend.
Pushing up against his limits sometimes "creates a cycle" in which he wears out himself and then appears fatigued during public events, Axios reported.
"He is his own worst enemy when it comes to his schedule," a former Biden aide said, according to Axios.
Biden has shown frustration with the perception that he's too old to be president.
"With regard to age, I can't even say, I guess, how old I am, I can't even say the number. It doesn't register with me," he said in April.
Despite his sensitivity about his age, Biden in recent months has accepted changes to help him stay healthy and avoid tripping. He's using the shorter stairs on Air Force One and wearing tennis shoes more often, Axios reported.
Reuters reported last month that Biden's age has become a defining part of the 2024 campaign. Even some Democrats have questions about his age.
Biden entered office as the oldest president and would be 86 at the end of a second term.
Former President Donald Trump, the clear front-runner for the 2024 Republican presidential nomination, frequently says Biden is too old for the job.
"We have a man that – he can't even walk off a stage," Trump, 77, said at a campaign rally in New Hampshire in October, Spectrum News reported. "He walks off the stage, just finishes his speech – he has no idea."
First lady Jill Biden and her staff are involved in forming the president's schedule.
A White House official told Axios that the Bidens keep "an eye on one another's schedules for the sake of balance — and they are far from the only couple in the administration who does that."
In his memoir, "Promise Me, Dad," Joe Biden wrote that Jill Biden would tell her husband's then-chief of staff, Steve Ricchetti, "Joe's working too hard. He's exhausted. He's not sleeping. It's going to kill him."