Is it time for Jumpin' Jack Flash to sit down and put his feet up? News that Mick Jagger is to undergo surgery to replace a heart valve will have come as a surprise to anyone who has seen the Rolling Stones on stage in recent years, where their hyperactive frontman still jerks incessantly about as if his bandmates filled his underpants with itching powder for a joke.
He may be 75 and have a face the texture of a leather suitcase that's been left out on a skip, but he cavorts with more energy than most performers half his age. Keith Richards, Charlie Watts and Ronnie Wood may be firing up the riffs but it is Jagger who personifies the physical vitality of the greatest rock and roll band in the world.
It is a little discussed aspect of the Jagger-Richards axis how they embody contrary aspects of rock's eternal spirit. Richards stands at a perilous angle and plays as if he is about to keel over, his disregard for his physical appearance reflecting rock's devil-may-care cool. He looks like he's ready to blow cigarette smoke in the face of the Grim Reaper.
Jagger jogs from side to side of the stage, twirls on the spot, runs up and down the catwalk, does his little fast foot shuffle, arms flying about, as if youth is a state of mind. He still wiggles his hips, for God's sake, when most of his generation have had theirs replaced.
But it turns out a Rolling Stone can gather moss, or at least furred arteries. The Stones have had to postpone the North American leg of their No Filter tour, which would have seen them play to a million fans over six weeks. Note the operative word there is postpone, not cancel. Jagger's statement said: "I will be working very hard to get back on stage as soon as I can."