By Adam Felman
Blood pressure is the amount of force that blood exerts on the walls of the arteries as it flows through them. When this pressure reaches high levels, it can lead to serious health problems.
In this article, we look at the causes of high blood pressure and how to treat it. We also explain the blood pressure measurements that health authorities consider to be healthy and too high.
Age, physical inactivity, and obesity can all increase the risk of high blood pressure.
The heart is a muscle that pumps blood around the body.
It pumps blood with low oxygen levels toward the lungs, which replenish oxygen supplies.
The heart then pumps oxygen-rich blood around the body to supply the muscles and cells. This pumping action creates pressure.
If a person has high blood pressure, it means that the walls of the arteries are constantly under too much force.
It is possible to divide the causes of high blood pressure into two categories:
- Essential high blood pressure: This type of high blood pressure has no established cause.
- Secondary high blood pressure: Another health problem is causing increased blood pressure.
Even though essential high blood pressure has no identifiable cause, strong evidence links specific factors to the risk of developing this condition.
The risk factors for essential and secondary high blood pressure include the following.
Age: The risk of high blood pressure increases as a person becomes older because the blood vessels become less flexible.
Family history: People who have close family members with hypertension have a significantly higher risk of developing it themselves.
Ethnic background: African-American people have a higher risk of developing hypertension than other people. Hypertension also presents more severely in African-American people and is less responsive to certain medications.
Obesity and being overweight: People who are overweight or have obesity are more likely to develop high blood pressure.
Physical inactivity: Lack of exercise and having a sedentary lifestyle raise the risk of hypertension.
Smoking: Tobacco intake causes the blood vessels to narrow, resulting in higher blood pressure. Smoking also reduces the blood’s oxygen content, so the heart pumps faster to compensate, causing an increase in blood pressure.
Alcohol intake: Drinking excessive amounts of alcohol can dramatically raise blood pressure and increase the risk of heart failure, stroke, and irregular heartbeat.
Poor diet: Many healthcare professionals say that a diet high in fats and salt leads to a high risk of hypertension. However, most dietitians stress that the problem is the type of fat rather than the amount.
Plant sources of fats, such as avocados, nuts, olive oil, and omega oils, are healthful. Saturated fats and trans fats, which are common in animal-sourced and processed foods, are bad for health.
Mental stress: Stress can have a severe impact on blood pressure, especially when it is chronic. It can occur as a result of both socioeconomic and psychosocial factors.
Excessive stress might also lead to actions that increase the risk of hypertension, such as consuming larger amounts of alcohol.
Diabetes: People with diabetes have a higher risk of developing hypertension. However, prescribed use of insulin and consistent blood sugar control can reduce the long-term risk of people with type 1 diabetes developing hypertension.
People with type 2 diabetes are at risk of hypertension as a result of high blood sugar, as well as other factors, such as certain medications, underlying cardiovascular disease, and being overweight or having obesity.
Pregnancy: Pregnant women have a higher risk of developing hypertension than women of the same age who are not pregnant. Preeclampsia is a placental disorder that can increase blood pressure to dangerous levels.
Sleep apnea: This sleep disorder, which causes people to stop breathing while asleep, might also lead to hypertension.
Signs and symptoms
A person with a headache, nausea, and blurred vision might be experiencing a hypertensive crisis. High blood pressure does not usually cause symptoms.
Most people with high blood pressure will not experience any symptoms. People often call hypertension the “silent killer” for this reason.
However, once blood pressure reaches about 180/120 millimetres of mercury (mm Hg), it becomes a hypertensive crisis, which is a medical emergency. At this stage, symptoms will show, including:
- a headache
- blurred or double vision
- heart palpitations
Anybody who experiences these symptoms should see their doctor immediately.
Children with high blood pressure may have the following signs and symptoms:
- a headache
- blurred vision
- Bell’s palsy, which is an inability to control the facial muscles on one side of the face.
Newborns and very young babies with high blood pressure may experience the following signs and symptoms:
- a failure to thrive
- respiratory distress
People with a diagnosis of high blood pressure should get frequent blood pressure checks. Individuals whose blood pressure is within the normal range should get a reading at least once every 5 years, while anyone with some of the risk factors above should have more frequent checks.
Without treatment or control measures, excessive pressure on the artery walls can lead to damage of the blood vessels, which is a form of cardiovascular disease. It can also damage some vital organs.
The extent of the damage depends on the severity of hypertension and how long it continues without treatment.
Possible complications of high blood pressure include:
- heart attack and heart failure
- blood clots
- kidney disease
- thickened, narrow, or torn blood vessels in the eyes
- metabolic syndrome
- brain function and memory problems
Treatment for high blood pressure depends on several factors, such as severity and the associated risks of developing cardiovascular disease or stroke.
The doctor will recommend different treatments as blood pressure increases:
Slightly elevated: The doctor may suggest some lifestyle changes for people with slightly elevated blood pressure who have a lower risk of developing cardiovascular disease.
Moderately high: If blood pressure is reasonably high, and the doctor believes that the risk of developing cardiovascular disease during the next 10 years is above 20 percent, they will probably prescribe medication and recommend certain lifestyle changes.
Severe: If blood pressure levels reach 180/120 mm Hg or above, this is a hypertensive crisis. An immediate change to the type or dosage of medication may be necessary.
Moderate exercise can help reduce blood pressure.
In 2017, the American Heart Association (AHA) issued guidelines introducing lifestyle adjustments that can help reduce blood pressure.
Discuss any planned lifestyle changes with a healthcare professional before introducing them.
Even walking for 30 minutes on 3–4 days of the week will usually reduce a person’s blood pressure by 4 mm Hg, according to an older study in Hypertension journal.
People should see the benefits quite soon after beginning an exercise program. Blood pressure will usually start to improve within a matter of 2 to 3 weeks, especially in people who are just embarking on a more active lifestyle.
A person should check with their doctor before embarking on any physical activity program and ensure that they tailor exercise to their own needs and state of health.
Exercise is most effective when it is regular. Exercising at weekends and doing nothing from Monday to Friday will be much less effective than exercising every other day, for example.
Studies have revealed that even moderate weight loss of between 5 and 10 pounds can make a significant contribution to lowering elevated blood pressure.
People who are overweight should aim to get closer to their healthy weight range. Blood pressure is likely to fall as a result. Weight loss will also improve the effectiveness of blood pressure medications.
Achieving a healthy body weight involves a combination of exercise, a healthful diet, and at least 7 hours of good quality sleep each night. Keeping a food diary can also improve the effectiveness of a weight loss program.
For more advice on maintaining weight loss, click here.
Some low-quality studies have shown that certain relaxation techniques, including yoga, meditation, and guided breathing, can have a short-term and low-level impact on blood pressure.
The AHA issued a statement noting that there is modest evidence to support the efficacy of some meditation techniques in reducing blood pressure.
A 2014 review found some very low-quality evidence in support of yoga as a way to manage hypertension. However, the authors noted that yoga was no more beneficial for hypertension than regular exercise.
Relaxation techniques may be more effective at an earlier stage of elevated blood pressure.
Although increasing sleep alone cannot treat hypertension, sleep deprivation and poor sleep quality have strong links to high blood pressure.
A 2015 analysis of data from a Korean national health survey found that hypertension was significantly more common among the participants who had less than 5 hours of sleep per night.
However, while improved sleep may support active treatment for high blood pressure, it is not a standalone solution.
Below are some of the most common drugs for treating high blood pressure. Some people might require a combination of several different medications.
1) Angiotensin-converting enzyme inhibitors
Angiotensin-converting enzyme (ACE) inhibitors block the actions of some hormones that regulate blood pressure, such as angiotensin II. Angiotensin II causes the arteries to constrict and increases blood volume, resulting in increased blood pressure.
People with a history of heart disease, women who are pregnant, and individuals with conditions that affect the blood supply to the kidneys should not take ACE inhibitors.
Doctors may order a blood test to determine whether the individual has any pre-existing kidney problems. ACE inhibitors can reduce the blood supply to the kidneys, making them less effective. As a result, regular blood tests are necessary.
ACE inhibitors may cause the following side effects, which usually resolve after a few days:
- a persistent dry cough
If a person finds the side effects too unpleasant or long-lasting to manage, a doctor may prescribe an angiotensin II receptor antagonist instead.
Side effects are less common with these alternative medications, but they may include dizziness, headaches, and increased potassium levels in the blood.
2) Calcium channel blockers
The primary effect of calcium channel blockers (CCBs) is to decrease calcium levels in the blood vessels.
A drop in calcium relaxes the vascular smooth muscle. The muscle contracts less strongly, resulting in the widening of the arteries, which leads to reduced blood pressure.
People with a history of heart disease, liver disease, or circulation issues should not take CCBs.
Individuals using CCBs may experience the following side effects, which usually resolve after a few days:
- redness of the skin, usually on the cheeks or neck
- swollen ankles and feet
- skin rash
- swollen abdomen, in rare cases
3) Thiazide diuretics
Thiazide diuretics act on the kidneys to help the body get rid of sodium and water, resulting in lower blood volume and pressure. They are often a doctor’s first choice of high blood pressure medication.
Thiazide diuretics may cause the following side effects, some of which may persist:
- low blood potassium, which can affect both kidney and heart function
- impaired glucose tolerance
- erectile dysfunction
People taking thiazide diuretics should receive regular blood and urine tests to monitor their blood sugar and potassium levels.
Those over 80 years of age may need to take indapamide (Lozol), a particular type of thiazide diuretic that helps reduce the risk of death from stroke, heart failure, and some other types of cardiovascular disease.
Beta-blockers were once very popular for the treatment of hypertension. Nowadays, people are more likely to use them when other treatments have not been successful.
Beta-blockers slow the heart rate and reduce the force of the heartbeat, causing a drop in blood pressure.
These drugs may cause the following side effects:
- cold hands and feet
- slow heartbeat
The side effects below are also possible, but they are less common:
- disturbed sleep
- erectile dysfunction
Beta-blockers are often the standard medication for a hypertensive crisis.
5) Renin inhibitors
Aliskiren (Tekturna, Rasilez) reduces the production of renin, which is an enzyme that the kidneys produce. Renin plays a key role in the production of angiotensin I, a protein that the body converts into the hormone angiotensin II. This hormone narrows blood vessels and raises blood pressure.
Aliskiren blocks the production of angiotensin I to reduce levels of both angiotensin I and II.
By doing this, it causes the blood vessels to widen, resulting in a drop in blood pressure. As it is a relatively new medication, healthcare professionals are still determining its optimal use and dosage.
Aliskiren may have the following side effects:
- flu-like symptoms
- a cough
It is essential to read the packaging of any medication to check for interactions with other drugs.
A healthful diet can help reduce blood pressure.
Managing the diet can be an effective way of both preventing and treating high blood pressure.
A healthful, balanced diet includes plenty of fruits and vegetables, vegetable and omega oils, and good-quality, unrefined carbohydrates. People who include animal products in their diet should trim all the fat off and avoid processed meats.
Lowering salt intake
The World Health Organization (WHO) strongly recommend that their member states take active steps to reduce salt consumption across the whole population.
Reducing salt intake by 3 grams per day could have profound effects on cardiovascular health, reducing systolic blood pressure by 5.6 mm Hg in people with hypertension.
The AHA recommend limiting salt intake to no more than 2,300 milligrams (mg) every day, with a view to eventually reducing this amount to 1,500 mg. People in the U.S. currently consume an average of more than 3,400 mg of sodium daily.
Those who often lose large quantities of sodium in the sweat, such as athletes, do not need to reduce their salt intake to the same extent.
The DASH diet
Number of weekly servings for those eating 1,600–3,100 calories a day
Number of weekly servings for those on a 2,000-calorie diet
Grains and grain products
Mostly low-fat or non-fat dairy foods
Lean meat, fish, or poultry
Nuts, seeds, and legumes
Fats and candy
The National Institutes of Health (NIH) designed a way of eating to control blood pressure called the DASH diet. The AHA also recommend this diet for people with high blood pressure.
The DASH diet focuses on an eating plan that emphasizes fruits, vegetables, nuts, seeds, beans, and low-fat dairy products.
People who are following the diet should ensure that they eat three whole-grain foods each day.
The plan essentially uses a “pyramid” of healthful foods, with grains, fruits, and vegetables making up the foundation of the diet and fats, sweets, and meat forming the top of the pyramid, which represents much lower consumption.
In minimal amounts, alcohol may lower blood pressure. However, drinking too much, even in moderate amounts, might increase blood pressure levels.
People who regularly drink more than moderate amounts of alcohol will almost always experience elevated blood pressure levels.
Many studies report on the relationship between caffeine and blood pressure. They have conflicting conclusions but agree that moderating caffeine intake is advisable for people with high blood pressure.
Anyone whose blood pressure is 140/90 mm Hg or more for a sustained period has stage 2 high blood pressure.
Doctors will define a blood pressure reading under one of the following five categories:
- Normal: Less than 120/80 mm Hg.
- Elevated: 120–129/80 mm Hg. At this stage, a doctor will advise the individual to make lifestyle changes to return their blood pressure to the normal range.
- Stage 1: 130–139/80–89 mm Hg.
- Stage 2: Over 140/90 mm Hg.
- Hypertensive crisis: 180/120 mm Hg or above.
A person in hypertensive crisis may need a prompt change in medication if they give no other indications of problems. Immediate hospitalization may be necessary if organ damage has occurred.
There are two parts to a blood pressure measurement:
- Systolic pressure: This is the blood pressure when the heart contracts.
- Diastolic pressure: This is the blood pressure between heartbeats.
If blood pressure is 120/80 mm Hg, it means that the systolic pressure is 120 mm Hg and the diastolic pressure is 80 mm Hg.
A sphygmomanometer measures blood pressure.
Most people will have seen this device, which consists of an inflatable cuff that wraps around the upper arm. When the cuff inflates, it restricts blood flow.
A mercury or mechanical manometer measures blood pressure.
A doctor will often use a manual sphygmomanometer together with a stethoscope. With a digital sphygmomanometer, electrical sensors take all of the measurements.
Advances in new wearable technology mean that people can now keep track of their blood pressure at home. Read our review of the best home blood pressure monitors currently available for home use.
One blood pressure reading is insufficient to diagnose hypertension. Blood pressure can fluctuate during the day, and a visit to the doctor may cause the reading to spike due to anxiety or stress.
A recent meal may also temporarily affect blood pressure readings.
As the definition of hypertension is “repeatedly elevated blood pressure,” a healthcare professional will need to take several readings over a fixed period. They may take three separate measurements, each a week apart. Often, the monitoring goes on for longer than this before the doctor confirms a diagnosis.
People with extremely high blood pressure or signs of end-organ damage should receive an immediate diagnosis to enable prompt treatment.
End-organ damage is damage to major organs that the circulatory system feeds directly, such as the heart, kidneys, brain, and eyes.
Kidney disorder: If an individual with high blood pressure also has a urinary tract infection (UTI), urinates frequently, or reports pain along the side of the abdomen, they could have a kidney disorder.
If the doctor hears the sound of a rush of blood when they place a stethoscope on the side of the abdomen, this could be a sign of stenosis. Stenosis is the narrowing of an artery supplying the kidney.
Additional tests for high blood pressure
The doctor may order the following tests before confirming a hypertension diagnosis.
Urine and blood tests: The underlying cause of high blood pressure might be an infection, a kidney malfunction, or high levels of cholesterol, potassium, or blood sugar. Protein or blood in the urine may indicate kidney damage, while high glucose in the blood might be due to diabetes.
Exercise stress test: An exercise stress test is a more common test for people with borderline hypertension. It usually involves pedaling on a stationary bicycle or walking on a treadmill.
The test assesses how the cardiovascular system responds to a spike in physical activity.
It is vital to declare a hypertension diagnosis before the start of the test. The test monitors the electrical activity of the heart, as well as the blood pressure during exercise.
An exercise stress test sometimes reveals problems that might not be apparent when the body is at rest. The doctor might take imaging scans of the blood supply to and from the heart.
Electrocardiogram (ECG): An ECG tests electrical activity in the heart. This test is more common in people with a high risk of heart problems, such as hypertension and elevated cholesterol levels.
Healthcare professionals call the initial ECG a baseline. They might compare subsequent ECGs with the baseline to reveal any changes, which might point to coronary artery disease or thickening of the heart wall.
Holter monitoring: For 24 hours, the individual carries an ECG portable device that connects to their chest through electrodes.
This device can provide an overview of blood pressure throughout the day and show how it changes as the level of activity varies.
Echocardiogram: This device uses ultrasound waves, which show the heart in motion. The doctor will be able to detect problems, such as thickening of the heart wall, defective heart valves, blood clots, and excessive fluid around the heart.
High blood pressure is a health problem that often causes no symptoms but can lead to severe health complications. Some underlying conditions can cause high blood pressure, but the exact cause of other cases is unknown.
Age, race, sex, lifestyle, family history, pregnancy, and stress can all contribute to high blood pressure, which can increase the risk of stroke and heart disease.
A healthful lifestyle and a balanced diet can help keep high blood pressure at bay.
A doctor will try to manage hypertension by recommending lifestyle changes, such as following the DASH diet, and prescribing medications.