US President Joe Biden arrives at Walter Reed Army Medical Center in Bethesda, Maryland, for his routine annual physical, on February 28, 2024.
US President Joe Biden arrives at Walter Reed Army Medical Center in Bethesda, Maryland, for his routine annual physical, on February 28, 2024. AFP

US President Joe Biden reported to a hospital Wednesday for his last yearly medical examination before November's election as scrutiny intensifies over the 81-year-old's fitness and mental acuity for a second term.

The White House said a summary of the test results taken at the Walter Reed military medical facility outside Washington would be released later in the day.

It will be closely followed for details about the health of America's oldest ever leader.

Biden, who is on course for a rematch with 77-year-old former president Donald Trump in November's vote, took a short helicopter ride to the medical center that often provides medical care for US presidents.

"I'm going to Walter Reed to get my physical," Biden said as he left the White House and reporters shouted questions at him.

Biden's routine medical exam comes as voter concerns mount over the age of a leader who would be 86 at the end of a second term in office.

The issue was thrust further into the spotlight earlier this month when a brutal special counsel report portrayed Biden as elderly and forgetful, giving ammunition to his Republican rivals.

The investigation cleared him of illegally retaining classified documents in his home and garage -- but said he would come across to a jury as a "well-meaning, elderly man with a poor memory."

Biden launched a fiery counterattack in a press conference at the White House, saying his memory was "fine" and slamming the special counsel for claiming he could not remember when his son Beau died of cancer.

But this week Biden took a lighter-hearted tone while trying to deflect the issue back onto his septuagenarian nemesis Trump.

In an interview with late-night TV comic Seth Meyers on Monday, Biden said he was a better bet than "the other guy" who was only a few years younger.

In last year's medical exam Biden got a clean bill of health, although he did have a cancerous skin lesion removed from his chest.

"President Biden remains a healthy, vigorous, 80-year-old male, who is fit to successfully execute the duties of the Presidency, to include those of as Chief Executive, Head of State and Commander in Chief," his doctor Kevin 'Connor, said following Biden's medical examination in 2023.