How (and why) you should reduce your blood pressure

What is hypertension? 

Hypertension is another term for high blood pressure and the point where it could be treated with medication. That’s set at 140/90, although, says MacGregor, to some extent that’s an arbitrary cut-off point. “The risks from high blood pressure don’t stop at a particular number. If you’re below that threshold but it’s still raised, you need to do something about it.” Hypertension carries no symptoms but it’s a huge risk factor for stroke and cardiovascular disease, the world’s leading cause of death, as well as other conditions including kidney disease, vision loss and vascular dementia. 

Blood pressure and age

“It goes up as we get older, so if you haven’t got high blood pressure now, you’re probably going to get it,” warns MacGregor. “In the UK, when you’re 20, your risk is roughly 20 per cent, at 50, it’s 50 per cent, at 80 years old, it’s 80 per cent.” Diet is thought to be the critical cause here – age-related increases in blood pressure have been observed in almost every population except hunter gatherers and forage farmers. In fact, salt is believed to be the culprit. 

“When you eat salt, you retain some in your body, which controls the amount of fluid in your blood,” MacGregor explains. “Put simply, it’s like adding fluid to a central heating system – it raises the pressure. There have been studies on communities who have no access to salt at all. Their blood pressure doesn’t rise with age – their average blood pressure is 92/60 – the same as a gorilla or baboon.” 

Why stress isn’t the problem 

It’s not uncommon to hear someone attributing high blood pressure to stress. In truth, stress itself is unlikely to be the cause or the answer. “If I pointed a machine gun at you, your blood pressure would go up, but the question is does stress cause a long-term rise in blood pressure? The evidence just isn’t there,” says MacGregor. Stress only becomes a factor if it leads to an unhealthy lifestyle – like eating badly, smoking, drinking and losing sleep. 

So what are the proven ways of reducing blood pressure? Experts way in on the best methods. 

Medication

Fortunately, we have very effective ways of reducing blood pressure with four main types of medicine. “They reduce blood pressure through different mechanisms and that’s important because your body will try to stop it working,” says MacGregor. “One tablet might reduce the pressure through one mechanism, and then if your body manages to block it, you might be prescribed another pill that works through a different mechanism. If you’re given two tablets that work in different ways, that’s more effective than one, and if you’re on three, that can be more effective than two.” 

The four main types are: ACE (angiotensin-converting enzyme) inhibitors and angiotensin receptor blockers (ARBs), which both work by controlling the hormones that help relax and widen the blood vessels, which in turn lowers the pressure; thiazide diuretics remove excess fluid from the body; and calcium-channel blockers (CCBs) prevent calcium from entering the cells of the heart and arteries (since calcium causes them to contract more strongly), allowing blood vessels to relax and open. 

Side effects for some include dizziness and headaches. “Some people won’t have any side effects. It depends on the drug and the person, and also whether they are on any other medicines,” says Ruth Goss, a senior cardiac nurse with the British Heart Foundation. “The long-term health consequences of uncontrolled high blood pressure are much worse. If you have any concerns about your medication, don’t alter the dose or stop taking it. Talk to your GP.”

Cut back on salt

This is absolutely key – the more salt you eat, the higher your blood pressure will be. Even if you are on blood pressure medication, a salty diet can make it work less effectively. Reducing your salt intake will have an impact quickly too – often within weeks. 

Though we need a small amount of salt to stay healthy – about 4 grams each day – we should eat no more than 6g, or one level teaspoon. Most of us eat too much. Roughly 75 per cent is from processed foods, 15 per cent is added during cooking or before eating (so remove the salt cellar from the table), and 10 per cent is found naturally in food.

When it comes to processed foods, check labels carefully for salt or sodium – two loaves of bread or boxes of cereal made by the same company can contain wildly different quantities. “When buying tinned fish, pulses or vegetables, opt for the ones in water over brine,” says Kate Llewellyn-Waters, author, nutritionist and resident expert on TV programme You Are What You Eat. Know your high-salt items – ketchup, soy sauce, gravy granules, processed meats, pickles, ready meals and takeaways. 

Opting for unsalted butter is one example of a simple swap you can make. The FoodSwitch app allows you to scan the barcodes of food and drink and instantly see whether they are high, medium or low in salt. It also suggests healthier alternative products.

“When cooking, one of the most effective tips to retrain your taste buds is to add herbs or spices in place of salt,” says Llewellyn-Waters. Lemon juice, cumin, shallots and fresh or dried herbs will all add flavour.”