High Blood Pressure / Hypertension

What is blood pressure?

Blood pressure, measured with a blood pressure cuff and stethoscope by a nurse or other healthcare provider, is the force of the blood pushing against the artery walls. Each time the heart beats, it pumps blood into the arteries, resulting in the highest blood pressure as the heart contracts. One cannot take his or her own blood pressure unless an electronic blood pressure monitoring device is used. Electronic blood pressure monitors may also measure the heart rate, or pulse.

Two numbers are recorded when measuring blood pressure. The top number, or systolic pressure, refers to the pressure inside the artery when the heart contracts and pumps blood through the body. The bottom number, or diastolic pressure, refers to the pressure inside the artery when the heart is at rest and is filling with blood. Both the systolic and diastolic pressures are recorded as "mm Hg" (millimeters of mercury). This recording represents how high the mercury column is raised by the pressure of the blood.

High blood pressure, or hypertension, directly increases the risk of coronary heart disease (heart attack) and stroke (brain attack). With high blood pressure, the arteries may have an increased resistance against the flow of blood, causing the heart to pump harder to circulate the blood.

The National Heart, Lung, and Blood Institute (NHLBI) of the National Institutes of Health (NIH) has determined two levels of high blood pressure for adults:

• Stage 1
  • 140 mm Hg to 159 mm Hg systolic pressure-higher number

    and

  • 90 mm Hg to 99 mm Hg diastolic pressure-lower number 
• Stage 2
  • 160 mm Hg or higher systolic pressure

    and

  • 100 mm Hg or higher diastolic pressure

The NHLBI defines prehypertension as:

• 120 mm Hg - 139 mm Hg systolic pressure

  and

• 80 mm Hg - 89 mm Hg diastolic pressure

The NHLBI guidelines define normal blood pressure as follows:

• Less than 120 mm Hg systolic pressure

  and

• Less than 80 mm Hg diastolic pressure

These numbers should be used as a guide only. A single elevated blood pressure measurement is not necessarily an indication of a problem. Your physician will want to see multiple blood pressure measurements over several days or weeks before making a diagnosis of hypertension (high blood pressure) and initiating treatment. A person who normally runs a lower-than-usual blood pressure may be considered hypertensive with lower blood pressure measurements than 140/90.

What are the risk factors for high blood pressure?

Nearly one-third of all Americans have high blood pressure, but it  is particularly prevalent in:

• persons with diabetes mellitus, gout, or kidney disease.
• African-Americans (particularly those who live in the southeastern United States).
• persons in their early to middle adult years; men in this age group have higher blood pressure more often than women in this age group.
• persons in their middle to later adult years; women in this age group have higher blood pressure more often than men in this age group (more women have high blood pressure after menopause than men of the same age).
• middle-aged and elderly people - more than half of all Americans age 60 and older have high blood pressure.
• persons whose parents or grandparents have/had high blood pressure.
• obese people.
• heavy drinkers of alcohol.
• women who are taking oral contraceptives.

How does blood pressure increase?

The following may contribute to an increase in blood pressure:

• being overweight
• excessive sodium intake
• a lack of exercise and physical activity

How is high blood pressure controlled?

Many people can control high blood pressure by:

• choosing foods that are low in sodium (salt).
• choosing foods low in calories and fat.
• choosing foods high in starch and fiber.
• maintaining a healthy weight, or losing weight if overweight.
• limiting serving sizes.
• increasing physical activity.
• reducing or omitting alcoholic beverages.

However, other people must take daily medication to control hypertension. People with hypertension should routinely have their blood pressure checked and be under the care of a physician.

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