THE body clock is the master of us all. But how we handle it is a matter of both mind and body.
Ryan Giggs, Tiger Woods and Didier Drogba this week met the challenges of keeping up appearances at the top.
Giggs, aged 40 and a half, was magnificent in Manchester United's comeback win over Olympiakos on Wednesday.
Woods, at 38, is painfully aware that his body might not allow his lifetime challenge to get close to Jack Nicklaus as golf's all-time winner of majors. The Tiger has what is called a bulging disc in his spine; trust me, it is as incapacitating as it sounds.
And Drogba? He will not say it but his displays show that, having turned 36, he is living on past performances.
There has been no specific injury for the great Ivory Coast striker. But what was clear on Tuesday - when the Drog returned to Stamford Bridge for the first time since he quit Chelsea with the Champions League trophy in his hands two years ago - is that he is no longer the force he was.
That was apparent even before he accepted a short-lived sinecure in the Chinese league. And before he took a halfway option of settling in Turkey.
Galatasaray is a big club on the Bosphorus. They have millions to spend on wages for old salts like Drogba and the Dutchman Wesley Sneijder who, though still only 29 and possibly with a big World Cup in him, plays as if he is in semi-retirement.
Istanbul straddles Asia and Europe. These two players, huge in their prime, are playing out their days, earning what they would get in Europe but performing in a halfway house.
Drogba had one shot, or rather fluffed one opportunity to shoot, in 90 minutes at Stamford Bridge.
He mentioned a possible return to the club where he played his best eight years.
Chelsea flattered him, Drogba deluded himself.
But why would anyone conclude that when Giggs showed United the way at Old Trafford 24 hours later?
There is no comparison between them - as players, as men, as physical specimens.
Giggs is still sprightly, resilient and able to stand out on a field of millionaires. Why? Because United use him sparingly (Tuesday was his first start since January).
He is no heavyweight who can muscle defenders aside the way Drogba used to do. Giggs has always been light on his feet and inspired in his creativity. Where once he outwitted opponents through speed, balance and trickery, he now sits deep in midfield.
He is protected there by Michael Carrick who will do the physical work and anchor the midfield. But what Giggs can do is convert ideas in the mind into spectacular passes.
He initiated the first two goals on Wednesday with passes struck 40m, struck with vision and imagination, and struck early so that the front runners Wayne Rooney and Robin van Persie could exploit gaps in the Greek defence.
That is now Giggs' role. He has the knowledge of almost 1,000 games. He has the eye to turn midfield into attack. And, in the mind, he is ahead of all the young runners around him.