It began with what I thought was a chest infection that wouldn’t shift. My lungs burned whenever I exerted myself. I ignored it. Men do. Then one day while cycling uphill from the Scottish Parliament, I collapsed in the gutter with a crushing weight on my chest that stopped me breathing. Even then I didn’t think it was heart trouble. I thought I had immunised myself against “Scotland’s disease” – our number one killer. I am fitter now than I was 20 years ago. I eat broccoli, for heaven’s sake. Even as I found myself being trundled into the cardiac ward, I remonstrated. Really, don’t waste your time. It must all be some kind of mistake. But it was not.

Back in the 1980s, when I worked for BBC Scotland, I remember being told that the reason the corporation’s pension scheme was so generous was because the average life expectancy of BBC employees after retirement was a year-and-a-half. It was probably apocryphal, but it rang true. In those days, far too many journalists never reached retirement. Hacks were notoriously self-destructive – smokers, drinkers, deadline junkies. Typical angry Scots who don’t look after themselves and don’t do emotion. But I was determined not to become just another statistic. So, after one too many funerals, I began to organise my life around not dying: proper diet, no smoking, exercise, moderate drinking. By the time I reached my 50s, I was pretty pleased with myself: I had low blood pressure, low cholesterol and was the ideal weight for my height. I knew I was fitter than I had been 20 years previously because I managed to climb Curved Ridge and the Aonach Eagach in Glencoe three or four times a year.

But then I discovered that Scotland’s number one preventable disease is nothing of the kind. An angiogram showed that key blood vessels were almost 90% blocked with cholesterol and plaque (a kind of hard connective tissue that forms in arteries around the heart). There was no doubt about it – my health-conscious lifestyle had in no way immunised me from the Scottish disease. I had the heart of a middle-aged overweight smoker who has lived on pies and spent his leisure time in the pub. In Springburn. Naturally, I felt just a little cheated. What was the point of all that good living if you still end up like this? I had ticked all the boxes, but somehow, the ticker hadn’t noticed.

I remonstrated unreasonably with the various doctors who had the misfortune to treat me. They all said roughly the same thing: “Look, you’re a male Scot. There’s really nothing you can do about it. Scottish men just get heart disease.”

At first, I accepted this as a ­statistical generalisation. However, the more I heard it the grumpier I became. What are they saying? Is it something in the Scottish genes? Is there something in the water? Are we on some kind of weird collective suicide trip?

In my own case, the genetic inheritance argument simply did not stand up. My father lived until he was 90 and never had any problems with his heart, and nor did his father, who lived to the age of 84. My mother reached 89, similarly untroubled by heart disease, and her father made it to 92. A Clyde shipyard worker, he lived a hard life. I remember my grandfather coming back from work with his hat sparkling with metal splinters. And always smoking. Both he and my father smoked Senior Service full-strength untipped cigarettes, all their working lives.

In my teens, I was a natural smoker, but by the time I left university I had already resolved to give up the weed – and I more or less did. You never entirely escaped from cigarettes, of course, because at the time I started working, everyone still smoked in offices. During the 1980s, smokers still regarded it as their constitutional right to pollute the atmosphere, and the rest of us just put up with it, sometimes tapping them for the odd fag out of nostalgia.

I suppose passive smoking could have laid the foundations for my own heart condition, but that doesn’t really make a lot of sense either. An ex-smoker’s lungs are supposed to revert to normal within seven years of giving up. As for general fitness, everyone says that exercise and good diet can prevent and even reverse blocked arteries. I have never eaten much dairy produce and have always been one of those boring people who really does eat five portions of fruit a day.

Was it perhaps the other scourge of the modern age, stress? It is widely believed that stress causes heart disease, but the actual evidence for this is pretty thin. The American Heart Association has long said that there is very little direct evidence that psychological stress has any direct connection with heart disease. It’s true that an extensive longitudinal study by the University of Helsinki in Finland found that stressed workers were more likely to die than those who weren’t, but that research was looking at real stress caused by living at the bottom of society’s heap. Its subjects were people doing menial jobs, with bad housing, poor wages and little control over their lives. The truth about stress is that it is a poor person’s disease; the stress experienced by television presenters and newspaper columnists doesn’t really count. In all countries, the unemployed are the group most likely to get heart disease, and Scotland is no exception.

There is some evidence that so-called “type A” hard-driving personalities are more prone to heart disease, though this whole area is controversial. I do get very frustrated and angry – mostly with computers. I am a poor timekeeper, habitually late for things – and I always seem to be bumping up against the next deadline. On the other hand, for an incorrigible procrastinator like me, deadlines are a kind of liberation – I’d never get anything done if I didn’t have them. They provide a structure for life – a peg on which to hang some kind of achievement. And when it comes down to it, is my job any worse than that of a teacher confronted by 30 offensive teenagers each day, or a postman doing a round of four miles an hour and taking home £13,000 a year? Probably not.

Could there be more profound existential factors at work – unaddressed emotional conflicts, neurotic anxieties, corrosive resentments or some other, new age, afflictions? Until relatively recently, it used to be commonplace to say that people “died of a broken heart”, and even though this makes little physiological sense, some still hold to the diagnosis. A friend of mine, Jo Clifford, the transgender playwright, had heart disease and puts it down, literally, to a broken heart following the death of his partner, Suzy. Since then Jo has given up being a man. “You have to listen to what your heart is telling you,” she says. “My heart told me I had to stop – just stop. My life, my work, was killing me.”

No, Jo does not advocate sex change as a preventative measure. But intuitively, you feel she must be right about intense emotion playing some kind of role. I went through a hellish divorce around the same time and I remember feeling my heart ache, quite literally, in the early mornings after waking up too early, or when thinking about the children. But medical science doesn’t recognise any such condition as a broken heart. Cardiologists are a hard-hearted lot and as far as they are concerned, lifestyle factors aside, heart disease is essentially a lottery. When your number is up ...

But this is a lottery that Scots males are particularly adept at winning. Which brings me back to the refrain that “Scottish men just get heart disease”. I have decided that there is a degree of inverted sexism in this. Recently, I was taken aback when a close female friend, on hearing about my condition, gave me a sharp dressing down about how “Scottish men just don’t look after themselves”, which in my case was laughably inappropriate.

This judgmental attitude has become quite commonplace, as a result of all those health education campaigns that suggest heart disease is avoidable if you live right. Perhaps it makes it easier to live with the prevalence of this killer if you think that, through their anger and loathing and unhealthy lifestyle, Scottish men are morally responsible for their own misfortune.

But why men? And why only in Scotland? Research among emigrants to Canada and Australia has established that within two generations, expatriate Scots acquire the mortality rate of the host nation. This is too short a time for any genetic adaptation to occur, which suggests that there is no genetic or racial factor in heart disease. Or rather, that it’s not enough just to be Scottish – you have to live here for the condition to be fatal. Some blame lack of sunshine, dark winters and the associated dearth of vitamin D. Meanwhile, there are public health researchers in Scotland who believe that some kind of social or cultural pathology is at work.

There is evidence that Scotland’s cardiac health is deteriorating relative to comparable regions in Europe. In fact, in 10 years’ time, according to a recent study by the Glasgow Centre for Population Health, the west of Scotland will have the lowest life expectancy in Europe. According to the report, in places like Silesia in Poland, mortality is falling faster, even though the region is far poorer than the west of Scotland. This has led people like Glasgow University’s Professor Phil Hanlon, the report’s co-author, to conclude that there might be a Scottish “X-factor” – perhaps something about the way Scots relate to each other – that explains why we do so much worse than anywhere else in Europe.

“This is a real challenge to us as a nation,” says Hanlon. “In Mediterranean countries, the extended family unit and a young man’s role in it seems to have remained stronger and it may have protected them from some of these effects.” In Scotland half of all children are now born out of wedlock.

His sentiments are echoed by writers such as Dr Carol Craig of the Centre for Confidence and Wellbeing, who has long argued that Scots’ low life expectancy may have something to do with the negativity, lack of confidence and low self-esteem that seem to define Scottish male culture.

However, this is fiercely contested by Scotland’s Chief Medical Officer, Harry Burns. He insists that there is no mystery about the nation’s poor health, which, he argues, can be explained with reference to unemployment and deprivation in west-central Scotland. “There is actually no evidence,” he tells me, “that Scottish males’ health risk factors are any worse than anywhere else in Europe.” In fact, take west-central Scotland out of the equation, and Scotland’s mortality from heart disease is the same as the rest of Europe.

Burns sounds a note of optimism. He argues that Scots are making the right changes – for example, by giving up smoking and taking exercise. Better treatment and earlier detection have halved mortality rates from heart attacks in the last decade, though there is an increase in the number of men seeking treatment for angina, the pain associated with coronary heart disease. There will always be a few people who buck the trend, he says, and it is wrong to suggest that my experience in any way diminishes the value of a healthy lifestyle.

And the good news is that the NHS in Scotland is now very good at dealing with heart disease. These days, truly amazing things can be done with minimal surgery. I, for example, have had stents – little lattice tubes – inserted into my arteries to unblock them. Witnessing surgeons conduct this procedure live on large television monitors was one of the most curiously moving experiences of my life.

Medical advances like these, and better drugs such as statins, have saved thousands of men from having to go through open-heart surgery. But the treatments are not infallible, and they don’t stop you having symptoms. I look pretty normal, but I still have angina. It comes on when my heartbeat rises above 120, which is depressing because it means not being able to go out in the hills. The worst thing is the drugs – four in the morning, three at night – which leave you feeling as if your head is on the wrong way.

When you have heart disease almost everything changes; yet at the same time, nothing does. Your heart becomes the prime focus of your existence, but ordinary life goes on and you just have to manage it. Emails still pile up, bills go unpaid, contacts get huffy that you haven’t called. And this is just how life is for the 620,000 Scots who currently suffer from heart and circulatory disease.

And be in no doubt: one day it could be you – no matter how many marathons you have run.