Patient information: High blood pressure in adults

HIGH BLOOD PRESSURE OVERVIEW

Hypertension is the medical term for high blood pressure. Blood pressure refers to the pressure that blood applies to the inner walls of the arteries. Arteries carry blood from the heart to other organs and parts of the body.

WHAT IS BLOOD PRESSURE?

An individual's blood pressure is defined by two measurements:

• Systolic pressure is the pressure in the arteries produced when the heart contracts (at the time of a heart beat)
• Diastolic pressure refers the pressure in the arteries during relaxation of the heart between heart beats.

Blood pressure is reported as the systolic pressure over diastolic pressure (eg, 120/70 or 120 over 70).

Untreated hypertension increases the strain on the heart and arteries, eventually causing organ damage. Hypertension increases the risk of heart failure, heart attack (myocardial infarction), and stroke.

HIGH BLOOD PRESSURE DEFINITION

The standard definition of high blood pressure is determined by the Joint National Committee (JNC) on Detection, Evaluation, and Diagnosis of High Blood Pressure. A person is considered to have high blood pressure after three to six elevated blood pressure measurements over several months. These definitions apply to adults who are healthy and not using medication for high blood pressure. If the two pressures fall in different categories, the higher one is used to determine the severity of the hypertension.

Normal blood pressure — Systolic <120 mmHg AND diastolic <80 mmHg

Prehypertension — Systolic 120 to 139 mmHg OR diastolic 80 to 89 mmHg

The term prehypertension was chosen because patients with blood pressures in this range are at increased risk of progressing to hypertension and developing cardiovascular complications.

Hypertension

        Stage 1: systolic 140 to 159 mmHg OR diastolic 90 to 99 mmHg
        Stage 2: systolic ≥160 mmHg OR diastolic ≥100 mmHg

Most adults with hypertension have essential or primary hypertension, which means that the cause of the high blood pressure is not known. A small subset of adults have secondary hypertension, which means that there is an underlying and potentially correctable cause.

HIGH BLOOD PRESSURE RISK FACTORS

Hypertension is a common health problem. In the United States, approximately 32 percent of African-Americans and 23 percent of white people and Mexican-Americans have hypertension.

Hypertension is more common as people grow older. As an example, among people over age 60, hypertension occurs in 65 percent of African-American men, 80 percent of African-American women, 55 percent of white men, and 65 percent of white women (graph 1 and graph 2).

Unfortunately, many people's blood pressure is not well controlled. According to the same national survey, hypertension was in good control in only 25 percent of African-Americans and whites and 14 percent of Mexican-Americans.

HIGH BLOOD PRESSURE SYMPTOMS

High blood pressure does not usually cause any symptoms.

HIGH BLOOD PRESSURE DIAGNOSIS

An individual's blood pressure varies with time and many people are anxious when seeing a healthcare provider. As a result, hypertension is not diagnosed unless the blood pressure is persistently high when measured at two office visits at least one week apart.

The only exceptions to this are if the blood pressure is very high or if there is evidence of damage from persistently elevated blood pressure, such as heart, eye, or kidney injury. Before a decision is made to begin treatment, a person is also encouraged to measure the blood pressure at home or work.

HIGH BLOOD PRESSURE TREATMENT

Untreated hypertension can lead to a variety of complications, including heart disease and stroke. The risk of these conditions increases as blood pressure rises above 110/75, which is still in the healthy range.

Benefits of treatment — In multiple studies of people with hypertension, those who were given blood pressure lowering medications for four to five years had a significant reduction in the number of coronary events, stroke, and death compared to those who did not receive treatment.

Treatment options

Lifestyle changes — Treatment of hypertension usually begins with lifestyle changes. Making these lifestyle changes involves little or no risk. Recommended changes often include a moderate restriction on salt in the diet, weight loss in those who are overweight or obese, avoiding excess alcohol intake, stopping smoking, and regular aerobic exercise (table 1). These changes are discussed in detail in a separate topic review. (See "Patient information: High blood pressure, diet, and weight".)

Medication — Antihypertensive medication is usually recommended when the blood pressure is consistently at or above 140/90 mmHg. Treatment with medication is recommended at a lower blood pressure (usually 130/80 mmHg) for people with diabetes or chronic kidney disease. (See "Patient information: Diabetes mellitus type 1: Overview" and "Patient information: Diabetes mellitus type 2: Overview" and "Patient information: Chronic kidney disease".)

The choice of antihypertensive drugs is discussed in a separate topic review. (See "Patient information: High blood pressure treatment in adults".)

SUMMARY

• Hypertension is the term for high blood pressure. This is the pressure of the blood against the inner walls of arteries, which carry blood from the heart. It is measured based upon two values: the systolic pressure measures pressure as the heart contracts and the diastolic pressure measures the pressure as it relaxes between beats. This is said as systolic pressure (eg, 120) over diastolic pressure (eg, 70) (see 'High blood pressure overview' above.
• Blood pressure normally changes over a person's lifetime (normally increasing with age) as well as over the course of a day. In addition, activity affects blood pressure, which rises as a normal response to physical activity and stress. However, patients with hypertension have high blood pressure even at rest.
• Untreated hypertension puts strain on the heart and arteries, eventually damaging such tissues, and is a key risk factor for heart failure, heart attack (myocardial infarction), and stroke.
• Normal blood pressure is defined as less than 120/80. Prehypertension is 120 to 139 mmHg over 80 to 89 mmHg. Patients with prehypertension are at increased risk of developing hypertension and heart and blood vessel complications. Hypertension is defined as greater than 140/90 (see 'High blood pressure definition' above.
• Hypertension is diagnosed if the blood pressure is persistently high after at least three office visits over several weeks to months. The only exceptions to this are if the blood pressure is very high or if there is evidence of damage from elevated blood pressure, such as heart, eye, or kidney injury. Before a decision is made to begin medication, a person is also encouraged to measure their blood pressure at home or work (see 'High blood pressure diagnosis' above.
• Treatment of high blood pressure significantly reduces the risk of heart problems (eg, heart attack) and stroke. Treatment usually begins with nondrug strategies, including moderate restriction on salt in the diet, weight reduction in those who are overweight, avoidance of excess alcohol intake, and regular aerobic exercise (see 'High blood pressure treatment' above.
• Antihypertensive medication is usually started when the blood pressure is persistently 140/90 mmHg or higher. On the other hand, drug treatment is warranted in patients with diabetes or chronic kidney disease who have a blood pressure that is greater than 130/80 mmHg. The choice of antihypertensive drugs is discussed in a separate topic review. (See "Patient information: High blood pressure treatment in adults".)

WHERE TO GET MORE INFORMATION

Your healthcare provider is the best source of information for questions and concerns related to your medical problem. Because no two people are exactly alike and recommendations can vary from one person to another, it is important to seek guidance from a provider who is familiar with your individual situation.

This discussion will be updated as needed every four months on our web site (www.uptodate.com/patients). Additional topics as well as selected discussions written for healthcare professionals are also available for those who would like more detailed information.

Some of the most pertinent include:

Patient Level Information:
Patient information: High blood pressure, diet, and weight
Patient information: Diabetes mellitus type 1: Overview
Patient information: Diabetes mellitus type 2: Overview
Patient information: Chronic kidney disease
Patient information: High blood pressure treatment in adults

Professional Level Information:
Ambulatory blood pressure monitoring and white coat hypertension in adults
Antihypertensive therapy and progression of nondiabetic chronic kidney disease
Approach to the patient with hypertension and hypokalemia
Can therapy be discontinued in well-controlled hypertension?
Cardiovascular risks of hypertension
Choice of therapy in essential hypertension: Clinical trials
Choice of therapy in essential hypertension: Recommendations
Diet in the treatment and prevention of hypertension
Hypertension: Who should be treated?
Hypertensive emergencies: Malignant hypertension and hypertensive encephalopathy
Indications for use of and contraindications to specific antihypertensive drugs
Initial evaluation of the hypertensive adult
Management of severe asymptomatic hypertension (hypertensive urgencies)
Overview of hypertension in adults
Patient adherence and the treatment of hypertension
Perioperative management of hypertension
Prehypertension and borderline hypertension
Renin-angiotensin system inhibition in the treatment of hypertension
Resistant hypertension
Salt intake, salt restriction, and essential hypertension
Screening for renovascular hypertension
Secondary prevention of cardiovascular disease: Risk factor reduction
Spontaneous intracerebral hemorrhage: Pathogenesis, clinical features, and diagnosis
Spontaneous intracerebral hemorrhage: Prognosis and treatment
Technique of blood pressure measurement in the diagnosis of hypertension
The metabolic syndrome (insulin resistance syndrome or syndrome X)
The prevalence and control of hypertension
Treatment of hypertension following a stroke
Treatment of hypertension in blacks
Treatment of hypertension in diabetes mellitus
Treatment of hypertension in heart failure
Treatment of hypertension in the elderly, particularly isolated systolic hypertension
What is goal blood pressure in treatment of hypertension?
Who should be screened for renovascular or secondary hypertension?

A number of web sites have information about medical problems and treatments, although it can be difficult to know which sites are reputable. Information provided by the National Institutes of Health, national medical societies and some other well-established organizations are often reliable sources of information, although the frequency with which they are updated is variable.

• National Library of Medicine

      (www.nlm.nih.gov/medlineplus/healthtopics.html)

• National Heart, Lung & Blood Institute (NHLBI)

      (www.nhlbi.nih.gov)

• American Heart Association

      (www.americanheart.org)

• The Hormone Foundation

       (www.hormone.org)

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