Blood pressure: from what values is it dangerous and which foods reduce the risk, explained by a cardiologist

High blood pressure is one of the most common conditions and can go undetected for many years, during which time it damages the heart, blood vessels, brain and kidneys. Often called the "silent killer", the condition can be prevented or managed through a balanced lifestyle. Dr Alexandru Covaciu, a consultant cardiologist, explained to Digi24.ro at what readings blood pressure becomes a concern, how it should be measured correctly, and which foods can help reduce the risk.

What is high blood pressure

High blood pressure refers to a persistent increase in the pressure that blood exerts on the walls of the arteries. Blood pressure readings naturally fluctuate throughout the day and can rise during physical exertion, stress, or intense emotion. A temporary increase does not necessarily indicate hypertension — a diagnosis is made when readings remain elevated across repeated measurements, taken correctly, at rest.

There is primary (essential) hypertension, which develops gradually due to genetics, age and lifestyle, and secondary hypertension, which has an identifiable cause, such as certain medical conditions or medications.

Blood pressure is expressed as two values: systolic (the higher number), which shows the pressure when the heart contracts and pumps blood, and diastolic (the lower number), the pressure in the arteries when the heart relaxes between beats. For example, at 120/80 mmHg, 120 is the systolic value and 80 is the diastolic value.

At what readings is treatment necessary

A blood pressure reading of 140/90 mmHg or higher, confirmed by repeated measurements, indicates high blood pressure and requires medical assessment and, where appropriate, treatment. For readings between 130–139/80–89 mmHg, the decision to treat is made on an individual basis, taking into account risk factors such as smoking, obesity, or a history of heart attack.

In patients with high cardiovascular risk, the ideal target may be around 120/70 mmHg. Drug treatment must be combined with lifestyle changes, and starting medication does not necessarily mean continuing it for life.

Hypertensive crisis — a medical emergency

Readings above 180/110 mmHg, especially when accompanied by symptoms such as headache, dizziness, blurred vision, chest pain, nausea or vomiting, may indicate a hypertensive crisis. In this case, 112 should be called immediately, without attempting to drive yourself to hospital.

The doctor warns against the risks of self-medication: taking a blood pressure medication without a prescription can cause a sudden and dangerous drop in readings. If blood pressure is elevated at home, it is recommended to re-measure correctly, and if readings remain high, medical assessment is necessary.

How to measure blood pressure correctly

Before measuring, it is recommended to rest for at least five minutes, seated, without talking, without using a phone, and without crossing your legs. Blood pressure should not be measured immediately after coffee, energy drinks or smoking, and the bladder should not be full.

At the first assessment, blood pressure should be measured in both arms; thereafter, in the arm with the higher reading. Two consecutive measurements are recommended, approximately five minutes apart.

People diagnosed with hypertension can monitor their blood pressure at home on a regular basis — for example, once or twice a week — as advised by their doctor. Even people without symptoms or a diagnosis can benefit from periodic checks.

For home monitoring, the doctor recommends an automatic upper-arm blood pressure monitor with a cuff sized to fit the circumference of the arm — wrist models are more sensitive to hand position and may give less reliable readings. The device should be checked periodically, including the battery, and a model validated by specialist medical societies is preferable.

Symptoms and complications

High blood pressure is called the "silent killer" because it very often produces no visible symptoms. A person may have elevated readings without being aware of it, and the first sign may be a serious complication, such as a stroke or a heart attack.

When symptoms do occur, they may include dizziness, headaches, pronounced fatigue, difficulty breathing or nosebleeds (epistaxis). These signs are not exclusive to high blood pressure and may have other causes.

Left untreated, high blood pressure can damage the heart, brain, kidneys and blood vessels, increasing the risk of stroke, heart attack and kidney failure, including the need for dialysis. It can affect the arteries of the lower limbs and, in severe cases, may lead to amputation. Another risk is aortic aneurysm (dilation of the body's main artery), and aortic dissection or rupture represents a major medical emergency with a risk to life.

Risk factors

The main risk factors include excessive salt and alcohol consumption, an unbalanced diet, a sedentary lifestyle, obesity and smoking, alongside chronic stress and insufficient sleep.

Obstructive sleep apnoea — repeated pauses in breathing during the night — is another significant risk factor. Loud snoring, particularly with breathing pauses observed by a partner, should be assessed by a doctor.

Age and heredity also contribute to risk, but a genetic predisposition does not mean that high blood pressure is inevitable.

Prevention and diet

For prevention, it is recommended to limit salt intake to approximately 5–8 grams per day, to be mindful of "hidden" salt in bread and processed meats, and to use iodised salt when adding salt to food. Daily and excessive alcohol consumption should be avoided; among alcoholic drinks, wine is considered less harmful than beer or spirits, though ideally alcohol should not be consumed regularly.

Regular physical activity — approximately 30 minutes, five days a week — a balanced diet, maintaining a healthy weight, 7–8 hours of sleep per night, and consistent monitoring of blood pressure are all important.

Foods that may help maintain normal blood pressure readings include beetroot, garlic, berries, olive oil, yoghurt and kefir. Some studies also suggest beneficial effects from green tea and hibiscus tea.