President Biden’s aides have provided insights into his daily routine, revealing that the president is most alert and engaged between 10 a.m. and 4 p.m., but experiences periods of confusion outside those hours, according to a new report.

The revelation comes in the wake of Mr. Biden’s performance in Thursday’s presidential debate, which left many Democratic supporters concerned due to his rambling answers and apparent disorientation.

According to aides who spoke with Axios, it is widely known within Mr. Biden’s inner circle that there seem to be two distinct versions of the president. One version is confident and focused; the other appears confused and tired.

The aides noted that Mr. Biden is only “dependably engaged” for a few hours each day, specifically from 10 a.m. to 4 p.m. Outside of those times, he is more likely to misspeak or seem lost.

During the 90-minute debate on Thursday, which began at 9 p.m., Mr. Biden appeared to struggle with maintaining his train of thought and completing sentences. His performance prompted concern within the Democratic Party, with former Obama adviser David Axelrod mentioning a “sense of shock” and suggesting that discussions about Mr. Biden’s future in the role might be necessary.

Some aides expressed that they were not surprised by Mr. Biden’s debate performance and voiced concerns about his fitness for another term. They reported that Mr. Biden’s limitations and mistakes are well known within the White House, with many staffers acknowledging the dual nature of his capabilities depending on the time of day and other factors, such as travel.

In response to these observations, White House spokesperson Andrew Bates told Axios, There is one Joe Biden, who he said “works his heart out fighting for families like the one he grew up in in Scranton, and who, because of his determination, experience, and decency, keeps achieving unprecedented results for them.”

But Mr. Biden himself acknowledged the changes in his abilities, saying at a campaign rally on Friday, “I don’t walk as easily as I used to. I don’t speak as smoothly as I used to. I don’t debate as well as I used to.”