What causes high blood pressure?

The cause of high blood pressure in most people remains unclear. We know that high blood pressure becomes more common as we get older and a variety of conditions and states — such as getting little or no exercise, poor diet, excess alcohol, and obesity,— can lead to high blood pressure. High blood pressure also tends to run in families.

How is blood pressure measured?

Your doctor or health care provider can check your blood pressure during a physical exam. (You can also check your own blood pressure at home.) Blood pressure is measured with a device known as a sphygmomanometer, which consists of a stethoscope, arm cuff, dial, pump, and valve. (A digital blood pressure monitor provides an electronic blood pressure reading.) The blood pressure reading is measured in millimeters of mercury (mm Hg), and is written as systolic pressure (the higher pressure when the heart is contracting) over diastolic pressure (the lower pressure when the heart is relaxed); for example, 120/80 mm Hg, or "120 over 80."

What is a normal blood pressure?

The Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure has classified blood pressure measurements into several categories:

  • "Normal" blood pressure: less than 120/80 mmHg
  • "Pre-hypertension": 120-139/80-89 mmHg
  • Hypertension: greater than 140/90 mmHg

What health problems are associated with high blood pressure (hypertension)?

Several potentially serious health conditions are linked to hypertension:

  • Atherosclerosis is a disease of the arteries caused by a buildup of plaque, or fatty material, on the inside walls of the blood vessels. Hypertension contributes to this buildup by putting added stress and force on the artery walls. Atherosclerosis can lead to heart attacks and strokes.
  • Heart disease includes heart failure (the heart can’t adequately pump blood), ischemic heart disease (the heart tissue doesn’t get enough blood), and hypertensive hypertrophic cardiomyopathy (enlarged heart).
  • In kidney disease, hypertension damages the blood vessels and filters in the kidneys, so that the kidneys cannot excrete waste products.
  • Hypertension can lead to stroke, either by contributing to the process of atherosclerosis (which can lead to blockages and/or clots) or by weakening the blood vessel wall and causing it to balloon and burst.
  • Eye disease can occur because hypertension damages the very small blood vessels in the retina.

How do I know if I have high blood pressure?

High blood pressure doesn’t cause any symptoms, so you usually don’t feel it. For that reason, high blood pressure must be diagnosed by a health care professional. If your blood pressure is extremely high, you might have unusually strong headaches, chest pain, and heart failure (especially difficulty breathing and poor exercise tolerance). If you have any of these symptoms, seek treatment immediately.

If I have high blood pressure (hypertension), how can I treat it?

Hypertension treatment usually involves changes in lifestyle at first, and, if necessary, drug therapy.

Lifestyle changes include:

  • losing weight
  • quitting smoking
  • eating a healthy diet, such as the Dietary Approaches to Stop Hypertension (DASH) diet
  • reducing the amount of salt in your diet
  • getting regular aerobic exercise (such as brisk walking)
  • limiting alcohol (no more than 2 drinks per day for men, and 1 drink per day for women and persons 65 years and older)

Hypertension medicines include angiotensin-converting enzyme (ACE) inhibitors, angiotensin receptor blockers, diuretics, beta blockers, and calcium channel blockers.

What are the side effects of high blood pressure (hypertension)medicines?

As is true with any medicine, hypertension medicines have side effects. Any medicine used to lower blood pressure can cause lightheadedness or dizziness if the blood pressure goes too low.

Other side effects may include:

What type of diet should I follow if I have high blood pressure (hypertension)?

A healthy diet, such as the Dietary Approaches to Stop Hypertension (DASH) diet, can go a long way toward lowering blood pressure. The DASH diet calls for a certain number of daily servings from various food groups, including fruits, vegetables, and whole grains.

The following steps can also help:

  • eating more fruits, vegetables, and low-fat dairy foods;
  • eating fewer foods that are high in saturated fat and cholesterol, such as fried foods;
  • eating more whole grain products, fish, poultry, and nuts;
  • eating less red meat and fewer sweets;
  • eating foods that are high in magnesium, potassium, and calcium.

When should I call my doctor?

If you are diagnosed with hypertension, it’s important to see your doctor on a regular basis. He or she can answer your questions during these visits.

However, there might be other times when you might need to speak to your doctor. For instance:

  • If you aren’t responding to the prescribed treatment and your blood pressure is still high — if this is the case, there might be other disorders that are causing your hypertension.
  • If you are having any side effects from the blood pressure medicine — if this happens, your doctor might wish to adjust the dosage of the medicine or put you on another medicine.

Are there any medicines that cause high blood pressure (hypertension)?

Some medicines that you take for another condition might cause hypertension. These include amphetamines, Ritalin, corticosteroids, hormones (including birth control pills), migraine medicines, cyclosporine, and erythropoietin.

Also, many over-the-counter medicines (such as those for cold, asthma, and appetite suppressants) can cause hypertension.

Don’t stop taking any prescribed medicine, including antihypertensive medicine, on your own without talking to your doctor.


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This information is provided by the Cleveland Clinic and is not intended to replace the medical advice of your doctor or health care provider. Please consult your health care provider for advice about a specific medical condition. This document was last reviewed on: 1/28/2013...#12272