Current and former White House officials have revealed a surprising limitation in Joe Biden's ability to meet presidential demands. According to these sources, the president's performance can vary significantly depending on the time of day.

Biden's cognitive abilities have been a recurring concern throughout his presidency. However, the recent debate hosted by CNN in Atlanta, Georgia, elevated these concerns to a new level, showcasing a Biden that many consider insufficient for the demands of the office.

From media outlets to analysts to Democratic Party members agreed that Biden's performance in the debate was severely lacking, representing a significant setback for his candidacy. Even Biden admitted his poor performance, saying: "I understand (...) I didn't have a great night."

But now, a report from Axios based on statements from eight current and former Biden officials, exposes that "time of day is important" in determining the amount of mistakes the president might make, suggesting that the event, which began at 9 p.m., was outside this optimal period and may have exacerbated his concentration problems and fatigue.

"From 10am to 4pm, Biden is dependably engaged — and many of his public events in front of cameras are held within those hours," White House aides said, adding that outside of this time slot, Biden is more likely to make verbal errors and become fatigued

The White House strategy for handling Biden's age.

The White House has implemented a series of strategies to manage concerns about Biden's age and health. These include closely managing his schedule, sleep schedule and even the type of shoes he wears, with the goal of maximizing his performance during critical times of the day.

Despite these efforts, Thursday's debate challenged these measures and showed a Biden who not only failed to live up to the expectations of some of his staff and donors, but also sparked concern.

CNN camera caught first lady Jill Biden helping her husband gingerly down the stairs after the debate, which visually underscored the president's physical limitations.

Only six hours effective

The debate has intensified doubts about whether Biden can meet the demands of another four-year presidential term, and now, these statements could further heighten the concern, since, according to White House aides, the 81-year-old president has only six hours a day to effectively perform in office, as long as he is not traveling overseas.