High Blood Pressure: Overview, Causes, Risk Factors, Treatment

High blood pressure (HBP) is a serious condition that can lead to coronary heart disease, heart failure, stroke, kidney failure, and other health problems.

"Blood pressure" is the force of blood pushing against the walls of the arteries as the heart pumps blood. If this pressure rises and stays high over time, it can damage the body in many ways.


About 1 in 3 adults in the United States has HBP. The condition itself usually has no signs or symptoms. You can have it for years without knowing it. During this time, though, HBP can damage your heart, blood vessels, kidneys, and other parts of your body.

Knowing your blood pressure numbers is important, even when you're feeling fine. If your blood pressure is normal, you can work with your health care team to keep it that way. If your blood pressure is too high, treatment may help prevent damage to your body's organs.

Blood Pressure Numbers

Blood pressure is measured as systolic (sis-TOL-ik) and diastolic (di-ah-STOL-ik) pressures. "Systolic" refers to blood pressure when the heart beats while pumping blood. "Diastolic" refers to blood pressure when the heart is at rest between beats.

You most often will see blood pressure numbers written with the systolic number above or before the diastolic number, such as 120/80 mmHg. (The mmHg is millimeters of mercury - the units used to measure blood pressure.)

Results from cross-sectional studies have shown that blood pressure, particularly systolic blood pressure (SBP), increases with increasing age. No age adjustment is made in setting the threshold value that defines high blood pressure. The classification of blood pressure outlined by the Joint National Committee on Detection, Evaluation, and Treatment of High Blood Pressure (JNC-VI), shown in Table 40.1, is the same for all adults irrespective of age. There were several minor modifications made in the JNC-VI revision of blood pressure classification that have major significance with respect to geriatric hypertension.

Hypertension: Classification, Epidemiology, Diagnosis, Evaluation and Treatment

The former category of isolated systolic hypertension [i.e., SBP > 160 mmHg and diastolic blood pressure (DBP) < 90 mmHg] was removed. In addition, the conjunction linking the systolic and diastolic blood pressure columns that define each stage was changed from "and" to "or." As a consequence of this new approach to classification and because isolated diastolic hypertension is so uncommon in older individuals, the correct categorization of blood pressure among those above age 60 may be made by using the level of SBP alone in 99% of cases. Thus, the SBP level matters for the purposes of classification. Finally, as is discussed, treatment recommendations are stratified, based in large part on the classification strategy shown ... more » »

Secondary Hypertension

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    Approximately 5% of patients with hypertension have specific causes (Table 11-3). The history, examination, and routine laboratory tests may identify such patients. In particular, patients in whom hypertension develops at an early age, those who first exhibit hypertension when over age 50 years, or those previously well controlled who become refractory to treatment are more likely to have secondary hypertension. Causes include renal disease, genetic causes, renal vascular hypertension, primary hyperaldosteronism, Cushing's syndrome, pheochromocytoma, coarctation of the aorta (uncommon), hypertension associated with pregnancy, estrogen use, as well as other causes (eg, hypercalcemia and medications) ... more » »

    The table below shows normal blood pressure numbers for adults. It also shows which numbers put you at greater risk for health problems.

    Categories for Blood Pressure Levels in Adults (measured in millimeters of mercury, or mmHg)

    Category Systolic
    (top number)
    (bottom number)
    Normal Less than 120 And Less than 80
    Prehypertension 120 - 139 Or 80 - 89
    High blood pressure      
         Stage 1 140 - 159 Or 90 - 99
         Stage 2 160 or higher Or 100 or higher

    The ranges in the table apply to most adults (aged 18 and older) who don't have short-term serious illnesses.

    Risk Factors for High Blood Pressure

    Having certain medical conditions can increase your chances of developing high blood pressure. These conditions include

    • Prehypertension.
    • Diabetes.

    Unhealthy behaviors can also increase your risk for high blood pressure, especially for people who have one of the medical conditions listed above. Unhealthy behaviors include

    • Smoking tobacco.
    • Eating foods high in sodium and low in potassium.
    • Not getting enough physical activity.
    • Being obese.
    • Drinking too much alcohol.

    Facts and figures

    Nearly 2 out of 3 adults with high LDL cholesterol and about half of adults with high blood pressure don't have their condition under control.

    About 70 million American adults (29%) have high blood pressure - that's 1 in every 3 adults.

    Approximately 16 million people in the UK have high blood pressure.

    High blood pressure was a primary or contributing cause of death for more than 360,000 Americans in 2013 - that's nearly 1,000 deaths each day

    High blood pressure is the main risk factor for stroke and a major risk factor for heart attack, heart failure and kidney disease. There is also increasing evidence that it is a risk factor for vascular dementia.

    High blood pressure is a level consistently at or above 140mmHg and/or 90mmHg.

    30 per cent of women and 32 per cent of men have high blood pressure.

    Up to the age of 64 there are higher rates of men with high blood pressure than women.

    People with high blood pressure are three times more likely to develop heart disease and stroke and twice as likely to die from these as people with a normal blood pressure.

    Approximately 62,000 unnecessary deaths from stroke and heart attacks occur due to poor blood pressure control

    High blood pressure rarely has any symptoms, the only way for people to know if they have the condition is to have their blood pressure measured

    Approximately one third of people with high blood pressure do not know that they have it.

    More than 90 per cent of people with high blood pressure who are receiving treatment are not controlled to 140/90 mmHg.

    Most people with high blood pressure who need to take medications, will need to take two or more to ensure that their blood pressure is lowered down to a target of 140/85mmHg

    Among women, levels of high blood pressure increase as income decreases.

    The risks increase as blood pressure rises, whether you have high blood pressure or a normal blood pressure - between the age of 40 and 70, for every rise of 20mmHg systolic or every 10mmHg diastolic the risk of heart disease and stroke doubles; for the range 115/75 up to 185/115mmHg.

    About 70% of those with high blood pressure and took medication had their high blood pressure controlled. The control rate was 46.6% among all hypertensive patients.

    25% of American adults have prehypertension-blood pressure numbers that are higher than normal, but not yet in the high blood pressure range.

    Prehypertension raises your risk for high blood pressure.

    Cardiovascular diseases kill more than 800,000 adults in the US each year. Of these, 150,000 are younger than age 65.


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