Biden's aides are terrified the 81-year-old's shuffle is making him look too old... so they now have him surrounded by protective staff

President Joe Biden's aides worry his shuffling gait and solo walk to Marine One have made the 81-year-old look even older, so they are now joining him on the march from the White House to the presidential helicopter. 

The aides think that having themselves walk between Biden and journalists' cameras will draw less attention to Biden's halting and stiff walk, Axios reported.

Voters have expressed concern about Biden's age as he seeks a second term. An NBC poll earlier this month found that the idea that Biden 'may not have the necessary mental and physical health to be president for a second term' was a top concern for voters. 

President Joe Biden walks to the White House last week with senior members of his staff, including Deputy Chief of Staff Bruce Reed, Senior adviser Mike Donilon, and Deputy Chief of Staff Annie Tomasini 

It was Biden who suggested aides walk with him as the president seeks to counter the concerns. 

'Weeks ago the President mentioned to aides that he'd prefer a less formal approach and said they should just walk with him,' a White House aide told DailyMail.com 

Since mid-April, he's had deputy chiefs of staff Annie Tomasini and Bruce Reed, top adviser Mike Donilon and press secretary Karine Jean-Pierre at his side as heads to Marine One.

In March, Biden's five walks to and from Marine One at the White House were by himself, or with family members. Starting April 16, Biden was joined by staff or lawmakers nine out of 10 times he walked to and from Marine One, per Axios' count.

The White House has tried to turn questions about Biden's age into an argument that he is the most experienced person to hold the office.

But as voters continue to fret in a way about Biden that they don't about Trump, who is 77, there's been a subtle shift in strategy. If Biden wins a second term, he would be 86 at its completion.

Biden is now making jokes repeatedly about his age.

At an event in New York on Thursday, when talking about the size of microchips being made at the factory he was visiting, Biden quipped: 'It's 4000 times thinner than a single hair on your head and I got some very thin hair on my head.'

He also likes to tell crowds that he knows 'he looks 40.'

His supporters are eating the jokes up, clapping loudly and cheering. 

President Joe Biden walked solo toward Marine One in March

President Joe Biden walks on the South Lawn after landing on Marine One with senior members of his staff including Bruce Reed and Karine Jean-Pierre

There have been other shifts.

The president has taken to wearing sneakers or hiking boots. He's been spotted lately sporting the Hoka 'Transport' sneakers, which typically retail for $150. 

He's also been using the shorter stair case on Air Force One, which has less steps, and doing balancing exercises. 

The president, 81, has taken several stumbles in his nearly three years in office - falling while boarding Air Force One, tripping on various staircases, and taking a dramatic tumble at the Air Force Academy when he encountered a sandbag. 

That smaller stair case - which goes into the belly of the 747 - is about half the size of the stair case that is used to access the upper part of the plane: 14 stairs versus 26. 

Biden's doctor has admitted the president has a stiff gait. 

In both reports on Biden's physicals, the president's physician, Dr. Kevin O'Connor, noted the president has suffered from a 'stiffened ambulatory gait.' Biden fractured his foot during the 2020 presidential campaign and had to wear a boot.

Otherwise, Biden has been declared fit to hold office.  

President Joe Biden arrives at the White House in his sneakers

President Biden also uses the shorter stair case on Air Force One

O'Connor recommended physical therapy - specifically 'proprioceptive maintenance maneuvers' - and shoe orthotics to help with his walking. 

Proprioception training focuses on the sense of body positioning in space and can involve balancing exercises, tai chi, and yoga.

Biden, who works out most mornings at the White House gym, has been doing balancing exercises with Drew Contreras, who was a physical therapist in the Army and worked with Barack Obama when he was in the White House.