Biden has faced mounting questions about his 2024 reelection bid after last week's shaky debate performance, with one House of Representatives fellow Democrat on Tuesday publicly calling on him to withdraw from the race.
The US President last returned from travel on 15 June, nearly two weeks ahead of the 27 June debate.
Speaking to donors at a fundraiser in Viriginia, the 81-year-old sought to allay concerns about his poor debate performance, whilst admitting his busy schedule may have drained him before the event.
Biden spoke as pressure remains high Wednesday morning for the president to withdraw his re-election bid and let another Democrat pursue the nomination.