Watching Mick Jagger's dangerously thin legs stalk about the stage in time to Jumpin' Jack Flash this weekend, I hoped in earnest that he had remembered to take his calcium and fish oil supplements.
The man will soon be 70 and, unless he has made a deal with the Devil at the crossroads like many of his blues forebears, his hips are bound to be feeling the strain of more than 50 years of intense gyration.
And Jagger is not alone. His enormous global fan base must be feeling the onset of old age, for the majority of them are similarly heading towards their dotage.
Despite their advancing years, though, The Stones and their fans can still pack a 20,000 seater stadium even though the tickets cost as much as £1,300 (Dh7,655). Indeed, the four nights of concerts originally planned - there are now five with one extra added in Brooklyn - are said to be netting the band as much as £25 million.
You have to be pretty wealthy to be a Stones fan. Their tickets are so overpriced that Jagger himself joked about them at the London concert on Sunday. "How are you doing in the cheap seats?" he quipped, then added: "They are not that cheap though."
The Stones have sold more than 200 million albums worldwide, and as for the merchandise - how many T-shirts have you seen with a pair of giant red lips on them? The Stones are a multibillion-dollar global brand that has managed to keep its core fan base on board for five decades.
And it is the spending power of the fans, rather than musical prowess of the band, that accounts for the longevity of The Stones.
For proof of this look at the life and music of someone such as Pee Wee Crayton, a Texas-born blues guitarist from whom The Stones, the Beatles and others borrowed many a riff.
Jagger himself would surely agree that Crayton's music is superior to his own. Indeed, it was a major influence on The Stones and all the bands that reinvented the blues in the 1960s.
Crayton, who was born in 1914, died penniless at the age of 70 as his fans were largely poor and black and lived in American cities just after the Great Depression. They certainly couldn't afford £1,000-plus concert tickets.
What sets fans of The Stones apart is the Baby Boom.
Baby Boomers, for those who do not know, were the 72 million or so Americans born between 1946 and 1964 at a rate of about 7.1 per minute. Consumerism was all but invented to sate their appetite for spending and The Rolling Stones wrote their anthems.
According to the latest data from Baby Boomer Magazine - yes they have their own publication - the group's spending power in the United States alone has reached some $3.9 trillion (Dh14.32tn) a year.
They account for just 26 per cent of the population but more than 40 per cent of the consumer economy. They have more discretionary spending power than any other demographic group and control some 70 per cent of the total net worth of US households - about $7tn in total. More than 80 per cent of all the cash in savings and loan accounts belong to the Boomers and they spend more on newspapers, magazines, movies, music and other media than any other group. And they have their equivalents with equally impressive spending power in Europe. In short the Baby Boomers are huge in number and very important players in the global economy.
The Stones did pretty well to get them on board at the very beginning of their existence, and even better to keep them on board for so long. But the Boomers won't be around for ever, not that Jagger will mind. As one of their number he will doubtless be ready to shuffle off just as the ticket sales start to wane.
The question is, who is coming up behind the Boomers to replace their awesome spending power and drive the global economy into the next century?
Similarly large demographic bulges in Asia and the Middle East ought to be big enough to fill the void. But it remains to be seen if ample education and employment opportunities will be on hand to provide such a large youthful population with the lifestyle the Boomers came to represent. If they are not this boom will be more of an economic burden than the bonanza of the post-war era.
Whoever the new Boomers happen to be, one thing is certain. Their soundtrack surely couldn't be better than the last.
