Is it the yoga, the early nights, the lack of butter on his toast or something else?
Whatever it is, we all want to know Ryan Giggs' secret.
His former teammate, Gary Neville, was in awe of the Welshman while commentating on Manchester United's 1-0 victory over Real Sociedad in the Champions League on Wednesday night.
Neville - who by all accounts was a manager's dream, a model professional - was forced to retire when he couldn't hack the pace of the game anymore, despite looking after his body as best as he could and never once straying from the rulebook.
But here he was, almost three years later, commentating on the Man of the Match display from an ex-teammate who is even older than him.
Giggs turns 40 next month, but you'd never have guessed it by the way he was charging about against a Real Sociedad side who have some immensely talented players, a few of whom are literally half the age of the man who has made more appearances for Manchester United than anyone else in history.
The flying left winger-turned-central midfielder made his senior debut for the Red Devils in 1990, back when Margaret Thatcher was still in power and Liverpool were still the powerhouses of English football.
Much has changed since then - not least in the world of football - but Ryan Giggs continues to play well for Manchester United, proving that he is the footballing equivalent of Peter Pan, an ageless wonder.
He may no longer be capable of terrorising defences in the way he once could, but his touch has certainly not deserted him, or his wonderful vision as we all witnessed against West Ham in the FA Cup at the start of this year.
Sadly, though, this is real life - not a Disney film - and the day will come, sooner rather than later, when Giggs is forced to hang up his boots as soon as he feels his performances hinder rather than help the team.
As a member of United's current coaching staff he will not outstay his welcome on the pitch, which is why we should make the most of this once-in-a-generation player while we still can.