Paul Vallely: Have I got Sharon Stone syndrome?

I was halfway through my morning swim yesterday when I realised that I hadn't telephoned the office as I had promised to do. Being a diligent kind of chap, I got out and went to the changing room and rang in from my dripping mobile.

Could I write something, they asked, about a new report that said that exercise could be a dangerous thing for people over the age of 40?

I could have just got dried, I suppose, but you can never tell with these reports. It might have just been the usual medical tit-for-tat whereby products such as olive oil, sugar or red wine are every few weeks discovered to be not as good/bad for you as had been previously asserted.

Or it might just be, I thought as I plunged back into the water, a plot by those who are too bone idle ever to bestir themselves searching for a medical excuse for their own indolence.

But no, when I eventually returned to dry land I discovered it was a new "syndrome". Doctors in California have applied to the American Medical Association for permission to register something called Stone Syndrome, in honour of the shapely 43-year-old film star Sharon of the same name, who was unfortunate enough to suffer a mild stroke last month while training for a three-mile charity run.

She is, apparently, not alone. There was Douglas Adams, of Hitchhiker's Guide to the Galaxy fame, who had a fatal heart attack aged 49 while peddling on the exercise bike in his Malibu home. And Jim Fixx, the man who reputedly invented jogging, who dropped dead on a run at the age of 52.

Indeed, researchers at Ohio State University claim there has been a massive increase in heart attacks and strokes among YMAs (the young middle-aged).

They reckon thousands have been killed by exercise as fortysomethings try to recapture the muscle tone of their youth.

That should make me safe, since I never had any tone in my youthful muscles. Indeed, I was one of those hapless creatures who, at school, was always the last to be picked when teams were being chosen for footie in the playground. My lack of eye-foot co-ordination kept me away from exercise for most of my life.

It was only after a heart scare earlier this year that I adopted my current fitness regime: half an hour in the gym on Monday and Wednesday evenings; the swimming pool on Tuesdays and Fridays; and the yoga class at the Buddhist Centre on Thursdays – topped up with weekend sessions when work has forced the odd weekday omission.

Certainly this does not put me in the same league of self-punishing exertion as Ms Stone. She had been spending more hours a day at her physical jerks than I do in a week. Her personal trainer, apparently, put her through a daily routine that includes yoga, a form of aerobic martial arts called Tae Bo and pilates – the currently trendiest form of body conditioning (pronounced puh-LAH-teez) – a system of exercises first devised for bed-bound invalids by attaching springs to hospital beds but which has become fashionable with Hollywood women such as Julia Roberts and Madonna because it improves body flexibility and strength without building bulky muscles.

The fact of the matter, of course, is that the vast majority of us do far too little, rather than far too much, exercise. And far more of us will eventually die from lack of exertion rather than from overdoing it.

The trick, I suppose, is, on the one hand, not to wait until you see the blue flashing light of the ambulance before buying a pair of trainers and, on the other, not to believe all the guff about no gain without pain. There is a key difference between pain and mere effort. It's a pity that so many people end up learning that the hard way.

p.vallely@independent.co.uk