President Joe Biden “continues to be fit for duty”, his doctor wrote after conducting an annual medical that is being closely watched as the 81-year-old seeks re-election in November.

Dr Kevin O’Connor, Mr Biden’s physician, wrote that the president is adjusting well to a new device that helps control his sleep apnoea and has experienced some hip discomfort but also works out five times per week.

“President Biden is a healthy, active, robust, 81-year-old male who remains fit to successfully execute the duties of the presidency,” Dr O’Connor said in a six-page memo on the president’s health, following a physical that took Mr Biden to Walter Reed National Military Medical Centre for more than two and a half hours.

His memo added that Mr Biden “feels well and this year’s physical identifies no new concerns”.

Marine One with President Joe Biden aboard lifts off from the South Lawn of the White House in Washington for a short trip to Walter Reed National Military Medical Centre (Andrew Harnik/AP)

The oldest president in US history, Mr Biden would be 86 by the end of a second term, should he win one.

His latest physical mirrored one he had in February last year when Dr O’Connor described Biden as “healthy, vigorous” and “fit” to handle his White House duties.

Still, voters are approaching this year’s election with misgivings about Mr Biden’s age, having scrutinised his gaffes, his coughing, his slow walking and even a tumble off his bicycle.

After he returned to the White House on Wednesday, Mr Biden attended an event on combating crime and suggested that when it came to his health “everything is squared away” and “there is nothing different than last year”.

He also joked about his age and people thinking “I look too young”.

President Joe Biden arrives at Walter Reed National Military Medical Centre (Evan Vucci/AP)

Former president Donald Trump, 77, is the favourite to lock up the Republican nomination later this month, which would bring him closer to a November rematch against Mr Biden.

Mr Trump was 70 when he took office in 2017, which made him the oldest US president to be inaugurated — until Mr Biden broke his record by being inaugurated at 78 in 2021.

Dr O’Connor’s report said that Mr Biden’s stiff walking was no worse than last year and was the result of arthritic changes in his spine.

He said the president also noted “some increased left hip discomfort”.

There were no signs of stroke, multiple sclerosis, Parkinson’s or other similar conditions in what the report called an “extremely detailed neurologic exam.”

Mr Biden, last summer, began using a continuous positive airway pressure, or CPAP, machine at night to help with sleep apnoea, and Dr O’Connor wrote that the president had responded well to that treatment and is “diligently compliant” about using it.

A recent special counsel’s report on the investigation into Mr Biden’s handling of classified documents repeatedly derided Mr Biden’s memory, calling it “hazy”, “fuzzy”, “faulty”, “poor” and having “significant limitations”.

It also noted that Mr Biden could not recall defining milestones in his own life such as when his son Beau died or when he served as vice president.

Still, addressing reporters the evening of the report’s release, Mr Biden said “my memory is fine” and grew visibly angry as he denied forgetting when his son died of brain cancer in 2015 at the age of 46.

White House press secretary Karine Jean-Pierre said that Dr O’Connor was one of a team of 20 different medical specialists who helped complete the physical.

Asked why Mr Biden was not undergoing a cognitive test as part of the physical, Ms Jean-Pierre said that Dr O’Connor and Mr Biden’s neurologist “don’t believe he needs one”.

“He passes a cognitive test every day, every day as he moves from one topic to another topic, understanding the granular level of these topics,” Mr Jean-Pierre said, noting that Mr Biden tackled such diverse issues as Wednesday’s crime prevention event before his planned trip to the US-Mexico border on Thursday and next week’s State of the Union address.

“This is a very rigorous job,” she added.

Many Americans, including Democrats, have expressed reservations about Mr Biden seeking a second term during this autumn’s election. Only 37% of Democrats say Mr Biden should pursue re-election, down from 52% before the 2022 midterm elections, according to a poll from The Associated Press-NORC Centre for Public Affairs Research.

Election 2024 Michigan
Republican presidential candidate former president Donald Trump speaks at a campaign rally (Paul Sancya/AP)

Mr Biden counters that his age brings wisdom, and he has begun to criticise Mr Trump for the former president’s recent public gaffes.

The president joked that his age was classified information and suggested during a taping in New York on Monday of Late Night With Seth Meyers that Mr Trump mistakenly called his wife Melania, Mercedes during a weekend speech at the Conservative Political Action Conference though the Trump campaign says he was correctly referring to political commentator Mercedes Schlapp.

Mr Trump has indeed had his own share of verbal miscues, mixing up the city and state where he was campaigning, calling Hungarian prime minister Viktor Orban the leader of Turkey and repeatedly mispronouncing the militant group Hamas as hummus.

More recently, he confused his Republican primary rival Nikki Haley with former Democratic House Speaker Nancy Pelosi.

While he was president, Mr Trump’s annual physical in 2019 revealed that he had gained weight and was up to 243 pounds.

With his 6ft 3in frame, that meant Mr Trump’s Body Mass Index was 30.4.

An index rating of 30 is the level at which doctors consider someone obese under this commonly used formula.

Wednesday’s report listed Mr Biden as 6ft tall and weighing 178lb.