Britain’s Covid-19 death toll makes grim reading — almost 180,000 people have lost their lives to the virus since the pandemic struck in 2020.
But during that same period, a ‘silent’ yet similarly deadly medical condition — high blood pressure — has killed almost as many. According to government estimates, in the past two years 150,000 people are thought to have succumbed to fatal strokes, heart attacks, dementia and kidney damage caused by high blood pressure.
It is a massive problem. More than one in four adults in the UK has high blood pressure, according to official data.
Indeed, the NHS has been involved in a long-running battle to reduce the damage high blood pressure (or hypertension) is doing to the nation’s well-being. This would then ease the financial burden of treating the long-term problems it causes — estimated at more than £2 billion a year.
But how to mount that battle is anything but straightforward. For simply defining high blood pressure is contentious. Some studies suggest the definition should be different for men and women. Even the methods used to check blood pressure are under question.
According to government estimates, in the past two years 150,000 people are thought to have succumbed to fatal strokes, heart attacks, dementia and kidney damage caused by high blood pressure
And while some campaigners believe that many more people should be treated for hypertension, others point to evidence that plenty stop taking blood pressure pills because of side-effects.
As it stands, the lack of symptoms — only 50 per cent of those with high blood pressure develop warning signs such as headaches, dizziness, breathlessness, nosebleeds or blurred vision — means many remain oblivious to the risk they face.
‘There are between five and eight million adults in the UK who need treatment for hypertension but are not getting it because they are not having their blood pressure checked regularly, so they have not been diagnosed,’ says Professor Graham MacGregor, chair of the charity Blood Pressure UK.
‘And the pandemic has almost certainly made things worse. People who might have had their high blood pressure picked up during face-to-face GP consultations were, for long periods, not able to see a doctor at all. Hypertension remains a major cause of death in the UK and there’s no evidence that mortality figures are coming down.’
Prevent hypertension before it takes hold
At the same time, studies show the number of people aged over 30 with high blood pressure has doubled worldwide since the early 1990s due to unhealthier lifestyles and ageing populations.
Action is needed — but the question is, what kind of action?
Blood pressure describes the strength with which your blood pushes on the sides of your arteries, and is measured in millimetres of mercury (or mmHg).
A reading consists of systolic pressure (the top number), which is the pressure in the arteries when the heart beats; and diastolic (the bottom number), which is the pressure in the arteries when the heart rests between beats.
If either figure is too high, this can place a strain on the arteries and major organs such as the heart. It may also increase the chance of blood clots, which can curb the oxygen flow to the brain and cause strokes.
Should doctors also be treating ‘pre-hypertension’, where the systolic readings are between 120 and 139? That was the finding of a 2021 study by the University of Oxford, involving almost 350,000 people. A file photo is used above
Blood Pressure UK says every two-point increase in the systolic reading above the normal range increases the risk of dying from heart disease by 7 per cent and a stroke by 10 per cent.
In the UK, high blood pressure is classed as anything above 140/90. Patients are usually prescribed tablets if they are unable to reduce their blood pressure through lifestyle changes such as increased exercise.
But should doctors also be treating ‘pre-hypertension’, where the systolic readings are between 120 and 139? That was the finding of a 2021 study by the University of Oxford, involving almost 350,000 people. Writing in The Lancet, the researchers found that for every five-point reduction in a patient’s blood pressure, the risk of heart attacks and strokes dropped by between 10 and 13 per cent.
And this wasn’t just the case in patients with sky-high readings, but also those with no history of cardiovascular trouble who were in the ‘pre-hypertension’ category.
The findings suggest millions in the UK who have healthy but borderline blood pressure should also be on daily pills, which mostly work by relaxing blood vessels so blood can flow more freely.
The Oxford researchers called for an overhaul of UK treatment guidelines so that patients who seem to be heading towards hypertension are treated before they get there.
In a statement at the time, the British and Irish Hypertension Society (BIHS) warned: ‘The UK is at odds with other parts of the world — such as some European countries and the U.S. — and it’s very likely that offering pills to more people with blood pressure lower than the threshold would prevent more heart attacks and strokes.’
‘We need to do better and there is a long way to go,’ says Professor Terry McCormack, president of the BIHS. ‘NHS England has set a target of getting 80 per cent of adults below the 140 mmHg threshold by 2029. At the moment the figure is around 46 per cent.’
Adding weight to the argument for a universal reduction in blood pressure was a review of 22 studies, also published in The Lancet last year, which found that lowering blood pressure by five points reduced the risk of developing type 2 diabetes by 11 per cent.
The University of Oxford authors said this is partly because cutting blood pressure reduces inflammation in the blood vessel walls which precedes the onset of type 2 diabetes.
Six-monthly jab to replace pills
Weight loss and exercise are normally the first things doctors suggest to tackle high blood pressure, but more surprising options are being identified.
In 2017, scientists in Germany found that high-salt diets in both mice and humans were killing off ‘friendly’ gut bacteria called Lactobacillus murinus.
These help to keep high blood pressure at bay by preventing inflammation in blood vessels that might restrict circulation, leading to a rise in readings.
Replacing the bacteria with the aid of daily probiotic yoghurts containing similar ‘friendly’ microbes seemed to push blood pressure down again, reported the journal Nature.
Other studies found having a healthy gut bacteria profile may also help blood pressure drugs work more effectively.
Around half of those prescribed tablets for high blood pressure in the UK stop taking them within 12 months — some are unable to tolerate the side-effects. But could a jab get around this?
Scientists from Queen Mary University of London and Barts Health NHS Trust are trialling a drug called zilebesiran, which is injected into the arm once every six months. It reduces levels of a hormone called angiotensinogen, which triggers the tightening of veins and arteries that drives up blood pressure.
Tests on 84 volunteers found one jab cut levels of the hormone by 90 per cent and significantly lowered blood pressure. A trial involving more than 600 people will run until 2025.
Despite pressure from some quarters, NICE opted not to lower the 140/90 target when it updated its treatment guidance for doctors earlier this year.
Professor McCormack, a member of the National Institute for Health and Care Excellence (NICE) committee that signed off on the guidelines, says it went for this target because a lower one would be unrealistic in the UK given the large number of people who would then need treatment.
In fact, the threshold for treating hypertension has fallen in the UK since the 1980s, when doctors rarely prescribed drugs unless the systolic blood pressure topped 180. But it’s still higher than in many other countries.
In the U.S. for example, guidelines call on doctors to intervene when patients get into the 120/80 ‘pre-hypertension’ danger zone. In most of Europe it’s 130/80.
‘Other countries are more proactive about pushing readings down,’ says Professor Melvin Lobo, a consultant in cardiovascular medicine at St Bartholomew’s Hospital in London.
‘But studies show that while this may have benefits, it also means more patients experience the side-effects of blood pressure drugs and so adherence becomes a problem — they’re less likely to take them.’
Research into the effects of changing the thresholds has yielded mixed results. A major study in the New England Journal of Medicine, in May 2021, looked at outcomes in 9,361 patients given medication to reduce their systolic blood pressure either to 120 or 140.
The risk of dying from heart attacks and strokes caused by hypertension was 27 per cent lower in the 120 group than among those aiming for 140.
But they were also much more likely to report serious side-effects such as hypotension (when blood pressure drops to 90/60 or less) as a result of treatment.
‘There’s no good data on the overall benefits of aiming for such a low level of blood pressure,’ says Professor Lobo. He adds that aggressive treatment in the elderly reduces the risk of strokes but also carries a greater risk of injury from falls brought on by fainting when blood pressure drops too low.
Indeed, NICE guidance states hypertension in the over-80s only needs treatment when the systolic reading exceeds 150.
There are multiple medications that can treat high blood pressure, which most people take for life. These include beta blockers to slow the heart rate, and ACE inhibitors which widen blood vessels. However, some people need to take more than one type.
‘The trick is to get readings down to the lowest level you can while making sure patients can tolerate the side-effects of the drugs,’ adds Professor Lobo.
Professor MacGregor says getting everyone’s readings down to 120/80 would potentially cut the number of strokes and heart attacks, but adds: ‘That could mean treating about 80 per cent of the adult population — do we really want that many people on drugs when the side-effects include fainting, which can lead to an increase in hip fractures in the elderly?’
Hypotension is a problem, too…
In fact, while most focus is on hypertension, having consistently low blood pressure (hypotension) causes problems, too, increasing the risk of dizziness, nausea, fainting, confusion and heart palpitations (see box above right).
High blood pressure drugs, such as beta blockers, can cause a severe dip in blood pressure when someone goes from a sitting to a standing position, as can some anti-depressants. Some people have naturally low readings — perhaps because of genetic factors — but hypotension can also be caused by diabetes (which can disrupt levels of hormones involved in blood pressure regulation), as well as neurological illnesses such as Parkinson’s disease.
The biggest risk factor for high blood pressure, meanwhile, is age — as we get older, blood vessels become less elastic, making it harder for blood to flow smoothly through the circulatory system.
Around 60 per cent of people over 65 in the UK have high blood pressure, compared to fewer than 5 per cent of those aged 16 to 24.
But questions are arising even about how blood pressure is taken. Checks usually involve sitting still while a ‘sleeve’ placed around the upper arm is inflated until blood flow is momentarily cut off.
A machine then measures the pressure placed on artery walls as the blood flows again. NICE guidance advises doctors to test both arms, and if one has a higher reading, to take that as the patient’s blood pressure status.
‘You may have narrowing of the arteries in one arm and not the other, which will affect your reading,’ says Professor MacGregor.
But what’s even more important, according to recent research, is to check readings as the patient moves from sitting to standing. Normally, the systolic reading dips slightly as we stand and more blood drains into the lower part of the body. But a team of scientists at the University of Padova in Italy have discovered that people whose blood pressure goes up rather than down when they stand face double the risk of a heart attack or stroke in the following ten to 20 years.
They tracked 1,207 young and middle-aged adults with borderline
high blood pressure (around or slightly above 140), but no history of heart disease, and measured changes in their blood pressure as they stood up.
The results, published in March in the journal Hypertension, showed that those most likely to later have a heart attack or stroke saw readings jump by around 11 mmHg. It’s thought the spike points to underlying hypertension which may not show up when patients are tested sitting down, or even when they wear a monitor round the clock.
The researchers said this should become a standard way to check blood pressure.
diagnosis may vary in women
some studies also suggest the threshold for diagnosing women should be reduced.
A study published in February 2021 by a team from the Cedars-Sinai hospital in Los Angeles, U.S., found women tend to have a lower ‘normal’ blood pressure range than men. They warned that pursuing a ‘one-size-fits-all’ approach was harming women’s health. The research, reported in the journal Circulation, analysed blood pressure readings from more than 27,000 people. It found that the risk of heart attacks and strokes in women started to increase significantly when their systolic measurement exceeded 110 mmHg, rather than 120 mmHg, where the dangers increase in men.
Professor Susan Cheng, a cardiologist who led the study, said: ‘We need to rethink what we thought was a normal blood pressure that might keep people safe from strokes or developing heart disease.’
The team are planning research into the benefits of treating women with tablets once they cross the 110 mmHg threshold.
In the meantime, says Professor McCormack, the UK needs to be more like Canada. Long regarded as one of the world’s success stories in tackling hypertension, 19 per cent of adults in the country are affected, compared to more than 25 per cent in the UK.
‘They routinely use pharmacies for measuring and treating high blood pressure and have local campaigns to raise awareness. It’s a more focused approach.’
Low blood pressure made me faint when I got up in the night
By Angela Epstein for the Daily Mail
Waking suddenly from the deepest sleep, I couldn’t believe how cold and hard the mattress felt beneath me.
It was only as I tried to get up that the reality became clear: I wasn’t in bed, I was face down on a bathroom floor.
All I remember was getting out of bed to go to the bathroom and then, nothing.
I had a painful, egg-shaped lump on the left side of my forehead and a metallic taste in my mouth, from a bloodied lower lip — which suggested I’d passed out face first.
Alone in a London hotel room, having travelled to the capital for work — my husband, Martin, was at home with our daughter, Sophie, 200 miles away in Manchester — there were no witnesses to what had happened.
Waking suddenly from the deepest sleep, I couldn’t believe how cold and hard the mattress felt beneath me, writes Angela Epstein, pictured
Thankfully I was able to see my GP the next day, who ran through possible causes.
It was only when the doctor cuffed my arm with a monitor that a likely explanation came to light: I had low blood pressure — a reading of 90/50 (normal is 120/80).
If the top number in a blood pressure reading goes below 100, as mine did, you are more likely to faint, explains Dr Jerome Ment, a consultant cardiologist at University Hospitals Birmingham NHS Trust.
‘Some people may be predisposed to low blood pressure and may not be aware of it until it reaches a critical level — triggered by, for example, dehydration — and it causes them to faint.’
Dehydration leads to a reduction in the amount of fluid in blood vessels and so pressure in blood vessels drops, adds Dr Glyn Thomas, a consultant cardiologist at the Bristol Heart Institute.
Suddenly standing from a sitting or sleeping position can also cause your blood pressure to drop, as it means the blood rushes to your legs, making you feel faint for a few seconds while the body adjusts.
Spooling back to the night of my faint, I realise that I’d been working late with nothing more than a salad and half a glass of tonic water since lunchtime and then I remember getting out of bed slowly.
‘If you’re deeply asleep, your heart rate and blood pressure are low, you’re in a nice, warm bed then suddenly get up, your body might not have time to acclimatise to the change,’ says Dr Thomas.
‘Gravity pulls the blood from the chest to the lower body and you don’t get enough blood to the brain, causing light-headedness and fainting.’
After tests ruled out other possible causes my only options were to make lifestyle changes such as taking care when getting out of bed and sleeping with the head slightly raised.
‘This encourages blood to pool in the lower body when you’re sleeping and tricks the body into thinking you are upright rather than lying down — so there is no sudden change in blood pressure when you stand up,’ says Dr Thomas.
‘Keep a glass of water by your bed and drink it when you wake up. Then wait for 20 minutes or so before getting up.’
Certainly I’m more cautious about not drinking enough fluid — I have no intention of sleeping anywhere other than a bed again.