These days more and more people are getting diagnosed with high blood pressure — but only a fraction of those with the condition have it under control.

High blood pressure “is a smoldering public health crisis”, said Dr Rishi Wadhera, an associate professor of medicine at Harvard Medical School in the US and an author of new research showing that blood pressure screenings have not returned to what they were before the coronavirus pandemic.

High blood pressure can raise the risk of heart attack, stroke, pregnancy complications and other health problems, but the symptoms are quite “often silent”, Dr Wadhera said.

“I worry it flies under the radar for many patients,” he added.

Here’s what to know about the hypertension issue, and how to get your blood pressure under control.

What’s normal

Blood pressure is the force that blood exerts against artery walls in the heart, said Dr Jim Liu, a cardiologist at the Ohio State University Wexner Medical Center in the US. You’ll always hear your blood pressure given as two numbers: the top number, known as systolic pressure, measures that force when the heart contracts. The bottom number, known as diastolic pressure, gauges the force when the heart muscle relaxes. It’s measured in units known as millimetres of mercury, or mm Hg.

You can have your blood pressure checked during a medical appointment or at a pharmacy, or you can check it yourself with a home monitor. The American Heart Association and the American College of Cardiology define normal blood pressure as below 120/80 mm Hg. The US Centres for Disease Control and Prevention defines high blood pressure as 130/80 mm Hg or higher.

Very high blood pressure can cause several symptoms including, but not limited to, severe headaches, chest pain and dizziness. For many people, however, blood pressure increases much too gradually for them to notice these issues, Dr Liu said.

High BP

High blood pressure forces the heart to work harder to pump blood. Over time, the overwhelmed heart can slowly start to falter and struggle to pump blood out to the rest of the body, a condition called heart failure.

The force and friction of high blood pressure can also injure the delicate lining of the arteries, Dr Liu said. Tears in the artery wall allow LDL cholesterol — also known as “bad” cholesterol — to latch on and form clumps, or plaques, in these gaps. This can block blood flow and, in some patients, cause a heart attack.

Blockages in arteries that carry blood to the brain can lead to a stroke. Long-term damage to blood vessels in the brain can also lead to a condition called vascular dementia, Dr Liu said.

What causes it

All arteries stiffen over time, leading blood pressure to climb steadily as people age. By age 75, an estimated 80 per cent of men and 86 per cent of women in the US have high blood pressure.

Multiple risk factors have been linked to high blood pressure, including smoking, heavy drinking, obesity and chronic stress. A lack of exercise and diets high in sodium and processed foods have also been associated with an increased risk of hypertension.

How to reduce it

For some people, lifestyle changes can be as powerful as medication, said Dr Martha Gulati, director of preventive cardiology at the Smidt Heart Institute at Cedars-Sinai in Los Angeles, US. She recommends at least 30 minutes of moderate exercise a day and sleeping seven to nine hours a night, both of which are associated with lower blood pressure. Maintaining or achieving a healthy body weight can also reduce blood pressure, Dr Gulati said.

Avoiding products that contain nicotine is important. Using nicotine drives up blood pressure, narrows blood vessels and may contribute to the hardening of arteries, according to the American Heart Association.

Some research suggests that following a low-sodium diet could reduce blood pressure by 2 to 8 mm Hg for some patients and that adopting the DASH diet — which emphasises fruits, vegetables and low-fat dairy products — could reduce blood pressure by eight to 14 points. Abstaining from alcohol or limiting consumption to no more than one glass per day for women and two glasses for men could reduce blood pressure by two to four points.

People who can’t lower their blood pressure to normal levels through lifestyle changes will need medication, Dr Gulati said. Water pills, or diuretics, help remove sodium and water from the body, bringing down blood pressure. Angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers both relax blood vessels, though they work in different ways. Calcium channel blockers help relax the muscle cells of blood vessels, and some slow your heart rate. People who can’t lower their blood pressure with these drugs may need additional medications. Doctors take a patient’s age, health and risk factors into consideration before deciding what medication to prescribe.

NYTNS