What remains intact is the indomitable will and the sense of devotion to his public.
When Muhammad Ali arrived in Hyde, Greater Manchester on a fundraising tour for his foundation, he was determined not to use the wheelchair that he relies on most of the time because of Parkinson's Disease.
Aided by his wife Lonnie and their host Ricky Hatton, who showed the couple round his gym, the legendary boxer raised his arm to greet the crowds.
Then for a few seconds he took off the sunglasses shading his eyes, allowing well-wishers to see his face more clearly .
Ecstatic supporters responded with cries of "Ali, Ali" and "You're still the greatest".
One local, 18-year-old Sama Ghafoor told the BBC: "I never thought this would happen in my life, and I can't believe it. What are the chances of him coming to Hyde?"
Once inside, the sports hero – who's in Britain to say goodbye to fans before he becomes too frail to travel – was presented with a cake. The initials on top read: 'GOAT' - Greatest Of All Time.
"He was going to come in a wheelchair initially but then he said I can't have Ricky Hatton meet me in a wheelchair, I've got to walk in," explained Ricky, himself a boxer.
"That's a boxer through and through. That's a boxer's mentality and that's a champion's mentality.
"He's not just one of the greatest boxers of all time, he's one of the greatest men of all time.
"Bearing in mind how poorly he is, for him still to come to the gym, raise his hands to the fans and have a picture, that's why he's the greatest."