It’s one of the biggest killers in the developed world – high blood pressure. People who seem to be outside the risk group also suffer from it: they are not overweight, do not smoke and eat healthy food. So what is the cause?
During a routine visit, my GP made a phrase that middle-aged people are afraid of: Blood pressure is slightly elevated. In fact, it was 150 / 95mm Hg, well above the level considered safe.
I have always assumed that I am at a low risk for stroke and heart disease: I don’t smoke, I am not overweight, I exercise regularly and eat plenty of green vegetables. Until forty, my blood pressure was around 120/80, usually considered ideal. Now, at the age of 47, I was diagnosed with grade XNUMX hypertension.
According to Professor Graham MacGregor, president of the Blood Pressure Association and professor of cardiovascular medicine at Barts and the London School of Medicine, I was lucky. Hypertension affects a quarter of the adult UK population and accounts for 60 percent of strokes and half of heart attacks. Since it is usually asymptomatic, most people are unaware of the risks. “High blood pressure is a silent killer,” says MacGregor. – You’re lucky it was discovered at a young age.
She’s probably right, but I don’t feel happy. I don’t like the prospect of taking pills for the rest of my life. The fact that defining hypertension is not easy does not help. Fifteen years ago, a score of 150/95 would not be of particular concern (the threshold was 160/100). But in the UK the bar is set at 140/90, while in the US the American Medical Association recently introduced a “prehypertensive” category for patients with blood pressure between 120/80 and 140/90.
There is also controversy over the effects of salt on blood pressure, and ideas for the new polypill, Sevikar HCT, to be prescribed to anyone over 55, which would make treatment for high blood pressure as common as water fluoridation.
The situation was not made easier by the recent discovery of 16 new genes related to blood pressure. When I first heard about it, I assumed genetic tests would be coming soon. Research by scientists from Barts and London included 200 people of European descent and 000 from outside Europe. They increased the total number of blood pressure genes identified so far to 75. However, while 000 percent of the gene variants are common to all population groups, taken together they have very little effect, reducing systolic blood pressure by less than 28 mmHg and diastolic blood pressure by 5 mmHg for the entire population (the first number is the blood pressure as the heart is pumping, the second – pressure between heartbeats).
As lead study authors Mark Caulfield and Patricia Munroe suspect, there may be hundreds of genes responsible for regulating blood pressure, each with very little effect – meaning useful genetic tests will not emerge soon.
Like many people for whom diet and weight do not appear to be a factor, I have long suspected that my high blood pressure has both genetic and emotional components. The mother, who is now 79 years old, has the second stage of arterial hypertension (160 / 100mm Hg or more) in her sixties. Scientists estimate that 30 percent of the changes in blood pressure seen are genetic. In addition, although my father’s blood pressure was always within the normal range, he was prone to mood swings (“hot blood”) and, like his father and grandfather, died of a heart condition in his seventies.
While it is difficult to tell if I have inherited a similar disposition, I am certainly prone to sudden, irrational fits of anger. Recent research by Peter Rothwell, professor of clinical neuroscience at the John Radcliffe Hospital, Oxford, found that blood pressure varies much wider than is commonly believed, and jumps sharply throughout the day and during the working week. “It is peak blood pressure, not average blood pressure, that is most strongly correlated with risk of stroke,” says Rothwell. The key to regulating blood pressure is to flatten these fluctuations.
To what extent does blood pressure depend on a person’s environment and temperament? It has long been known that the kidneys play a key role in both regulating blood pressure and the fight-or-flight response. These links suggest an evolutionary link between blood pressure and emotional and mental states. For some people, the mere fact that blood pressure is measured by medical professionals is enough to increase it (the white coat effect), while meditation and acupuncture temporarily lower the pressure. People who report higher levels of stress at home or at work, or have suffered from a difficult life event, such as the death of a spouse, are more likely to have a stroke or heart attack (in one study, work-related stress factors such as an impending deadline were associated with a six-fold increase in the risk of a heart attack). Frequent anger and hostility are also associated with problems with the coronary circulation.
Although experts’ opinions are divided, Rothwell points out that stress raises blood pressure, and people exposed to stressful situations have greater blood pressure variability. “When I’m presiding over an important meeting or giving a lecture series, my systolic blood pressure can go up to 180. It’s almost certainly due to stress,” says Rothwell. The bond between blood and emotions is embedded in everyday language – we are talking about “sanguines” or hot-blooded people, but the average family doctor usually has too little time for such observations
When we are young, the body adapts more easily to sudden fluctuations in pressure, but as we age, our blood vessels become harder and less flexible. This is a problem especially for Western countries and Asian societies such as Japan. Many experts believe salt is the cause.
The Brazilian Yanomami tribe, whose diets are low in salt and saturated fats and rich in fruit, have the lowest mean arterial pressure of any population on Earth – 95/61. It does not grow with age. In the West, where people eat an average of 10-12 grams of salt a day, blood pressure rises by an average of 0,5 mmHg per year. It may not sound like much, but in the average life it varies between 35 and 44 mmHg of systolic blood pressure. The latest meta-analysis of clinical trials involving 6000 people from around the world found that lowering salt intake by just 2 grams a day reduces the risk of cardiovascular events by 20 percent. According to Professor MacGregor, who also chairs Consensus Action on Salt and Health (Cash,), the relationship between salt and higher blood pressure is not questioned in serious scientific circles. But despite the scientists’ consensus, statements questioning the role of salt still attract media attention.
“The salt industry is trying to create the belief that the matter is controversial, and when experts cannot agree, how would the average person make an informed decision?” MacGregor says. “The fact is, we have seven or eight different kinds of evidence pointing to a role for salt. If you cut your salt intake in half, your blood pressure would drop.
The UK is currently the leader in reducing salt consumption. More than 40 food producers agreed to reduce the content of supermarket food by 40 percent by 2012, and by a further 15 percent in the following years. At the same time, NICE called for the average UK adult to cut salt consumption faster – to 6g a day in 2015 and 3g by 2025.
Despite the frenzy over the dangers of high blood pressure, most people are blissfully unaware. One of the biggest surprises for me was to discover that my diet is not as good as I thought – there have been days when I consumed as much as 10 g of salt, almost twice the recommended amount (this is a problem especially at Christmas: turkey for dinner adds about 15g).
After diagnosis, I eliminated processed foods and bread from my diet (a slice of bread contains an average of 0,5 g, so six a day is half the daily intake), and increased my fruit and vegetable intake. I put my coffee down and experimented with acupuncture, which, however, only relieved the pressure for a short time. Keeping in mind my father’s mood swings, I tried not to be irritated and to control my temper – not always with success. After reading about the benefits of having a dog (dogs are considered stress buffers), I acquired a fluffy white goldendoodle. Murphy certainly makes me leave the house more, which in itself may be healthier. On the other hand, it can be a source of stress – it has a tendency to steal children’s balls and runs down the road after stray cats.
I enrolled in a drug course and now take two tablets a day – a diuretic and an ACE inhibitor.
The good news is that four years later my mean blood pressure is 130/85 – far from perfect, but normal for a 51-year-old. The bad news: I will have to take medication for the rest of my life. Unless NICE changes the definition of hypertension by raising the risk threshold, then miraculously I would be back in the safe zone.
Text: Mark Honigsbaum
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