I will be 40 next year

I will be forty years old next year. I can't say I'm particularly happy about that. From the age of 22 I dreaded my impending 30th birthday, and thus I wasted most of my 20s. 40 has only really started to loom in the last few months.
I am currently part way through reading Richard Herring's excellent book (particularly if you like Richard Herring. If you don't like him, probably won't be your favourite book) How Not To Grow Up, about his own struggles with turning 40.
30, to be honest, really was just a number. Whereas nearing 40 I am getting some tangible signs of ageing.
I have had "a bad toe" for about 3 months now. The nail went manky, and it was agony every time one of my spawn stamped on it. Its finally clearing up, but things never used to take that long to heal.
I've had a cough for about 4 weeks now. Its turned into a chest infection. I'm on antibiotics and I've had to admit defeat and quit smoking. I'm resting. I genuinely don't feel well. I passed out whilst coughing, which scared the bejesus out of Mrs Langston, as she had to pound on my chest to restart my breathing.
I'm never ill! Never! Even though I weigh as much as Rosie (from "Whole Lotta" fame, ie nearly 19 stone). But she was supposed to have breasts, and I'm not.
Found out this morning that a friend of mine who I've known for 30 years (and that's far too long a time to be applicable to any aspect of life) had 2 strokes earlier this year.
Signs of mortality are on the increase. Not just that we all die. I've known that to be true, logically, for some time. The problem is that it is increasingly applicable to me specifically.
Hence the reason for most mid-life crises, I suspect - a desperate attempt to milk the most from what remains of life before it is gone.
But I've already had a red sports car. Already had a busty blonde girlfriend 10 years my junior (now my wife and mother of my two boys - rock and roll!). I already play at being young again in a rock band.
What else is available to me?
I don't drink any more, really. I have no desire to philander - my life needs simplifying not more complexity. What else can one do to recapture lost youth if not go on a self-absorbed rampage of self-destruction with collateral damage?
As I write this, I really hate the only logical conclusion. Not self destruction but self improvement. Lose weight, eat better, jog, exercise. Its entirely possible that the signs of mortality (aches, pains, illnesses, general decrepitude) would ease (or at least be replaced by some new aches and pains).
What a depressing conclusion to reach. I may have to make constructive efforts instead of self destructing. That can't be right, surely?
Sent using BlackBerry® from Orange