Tony should be careful...

Looking at the photos of a tense, pale Tony Blair in yesterday's papers, I actually spoke aloud to the photo: "Give up your job if you value your life." I don't care what the doctors say about his condition not being serious and that suffering supraventricular tachycardia is not a life-threatening heart problem.

He may be a fit man who eats healthily, doesn't smoke or drink to excess, but he's a man under enormous pressure and he's been given a wake-up call.

It's exactly what happened to me, and I know that when something like this happens you need to take stock and appreciate what you have - and that doesn't mean your job.

I'm convinced that the stress of my high-powered career as a successful property investor played the biggest part in my own wake-up call and I've completely changed the way I look at life now. Working so frantically and at such a rigorous pace inevitably means trouble. I'm sure that Mr Blair, in the same way as many men, takes good health for granted.

We forget the basic machinery that keeps us going, and how we must care for it, thinking nothing could ever happen to us, that we're invincible.

I'm 40 and before my heart problem five months ago, I took plenty of risks in my business life, constantly biting off more than I could chew. I'd have up to 10 very big deals in the air at the same time, and although I'd tried to slow down by cutting down on business trips abroad, I was in a constant state of anxiety. Yes, I smoked a handful of cigarettes a day, grabbed whatever food I could on the run and drank socially, but I still believe that stress was the most damaging factor.

Yet I still thought I was in good shape and that my stressful career was balanced by not being overweight, by going to the gym every morning and by hardly ever visiting the doctor. My blood pressure, cholesterol and family history were all fine. I took regular holidays with my wife, Sunny, and two boys, aged 15 and 12, and lived a happily married and luxurious life in my large home in Kingston, with four cars - including a beautiful Bentley - in the drive. So, as I rushed from one job to the next, I never assumed my heart was anything but healthy.

Then, one Sunday morning in May, my life changed irrevocably. I woke up feeling perfectly fine. We had just moved house and had been celebrating with friends until the early hours. Sunny and I left the boys with our nanny and went off to a furniture store in Park Royal where we were about to choose a new kitchen.

As we waited for a salesman, I felt some discomfort in my chest. I wouldn't describe it as painful, more a tightness, as if I'd pulled a muscle. I wasn't alarmed because we'd been moving heavy boxes around at home, so I assumed that had caused the problem.

But by the time we got back to the car, I had an overwhelming feeling that this was something serious, even though at that stage I recall thinking: "Whatever it is, it can't be my heart, I'm only in my forties!'' But I felt odd, dizzy and inexplicably nervous about what was happening in my body. I feel ridiculous about it now, but I turned to Sunny and said: "I need to say goodbye ... I think this is going to be my last day."

Sunny panicked and took over the driving and we rushed to the nearest A&E. As we walked in, the doctor standing at reception noticed my hand clutching my chest and took me straight to a cubicle. I was there for four hours, given an ECG and some medication and then I was told that I was fine. I felt a fraud and the first thing I did once I got to the car was smoke a cigarette.

That evening, my left arm and the top of my chest started to hurt, as though the muscles were all twisted. I called our GP and asked him to make a home visit, but he refused, saying he wouldn't come out for a muscular injury - which is what I still thought it was. He told me to take painkillers, which I did. Feeling better in the morning, I was moving boxes again. But by lunchtime I was almost screaming with pain and Sunny drove me to Kingston Hospital.

After an ECG and blood tests, the first thing the doctor said was: "I can't believe the hospital you went to yesterday let you go home. Your heart rhythm has been upset, and you've had a minor heart attack. It seems it happened yesterday."

With that, I was admitted to hospital, put on all kinds of clot- busting drugs, given glycerine- trinitrate to spray under my tongue to pump up narrowed arteries and an angioplasty - and there I stayed for three weeks.

Once the treatment took effect I felt fine, but I knew that, even as a fit 40-year-old, I had to change my life radically. Obviously, I stopped smoking and cut out all fatty foods from my diet. I have always hated salads, yet now I'm living off them. I was told to walk for half an hour every day, which I do religiously.

But although all these changes were of major importance, the doctors were particularly concerned about the huge amount of stress I was under; the long hours at work and the constant anxiety which was always with me. I may have appeared in control, but I worried about my deals, my staff, my family, my house, my cars - anything and everything. I was told I had to slow down, minimise the stress and pressures in my life and put my health and my family as the only priority.

So, no longer do I sit in my office doing deals on three phones at once while still having one eye on the computer. No longer do I rush from one meeting to the next without time to breathe, drive long distances to see clients or jet abroad at a moment's notice if a conference call will do. I guess I work roughly the same hours but I've made those hours far less pressurised. I am more relaxed during them.

"Stop worrying" is what the doctors all say, but that's easier said than done; the only way to stop worrying is to give yourself less to worry about by getting out of stressful situations. After my heart attack, my brother, who is 46, was concerned that he might be at risk, too. So he was tested for homocysteine, the chemical in the blood which is raised by stress and gives a strong indication of the health of the arteries.

Thank goodness, he appears to be okay, but he has now also changed his lifestyle for the better, as he doesn't want to take any chances. There is a new DIY test kit for homocysteine on the market and I shall be checking mine - along with other routine hospital checks - regularly from now on.

Tony Blair's condition is said to be "minor", but I'd say it's certainly a warning. How a man with a pressurised job like that can sleep peacefully at all I cannot imagine. It must be impossible for him to switch off even when he's on holiday with his family. From where I'm sitting, he looks as though he could be in big trouble, whatever the doctors say. "Pack up Tony" is my advice. Granted, the PM may have the top job, but nothing is worth your life.