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.
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.
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.
Symptoms of high blood pressure
High blood pressure itself usually has no signs or symptoms. The condition can damage your heart, blood vessels, kidneys and other parts of your body if it goes undiagnosed. That's why knowing your blood pressure numbers and checking them regularly is important.
When blood pressure stays high over time, it can damage the body and cause conditions such as:
- heart failure
- kidney failure
- heart attack
- vision changes or blindness
Risk factors of 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 U.S.)
- 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
The following may contribute to an increase in blood pressure over time:
- being overweight
- excessive sodium intake
- a lack of exercise and physical activity
Diagnosis of high blood pressure
The National Heart, Lung, and Blood Institute (NHLBI) of the National Institutes of Health (NIH) has determined two stages of high blood pressure for adults; 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 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.
- 140 to 159 systolic pressure (top number)
- 90 to 99 diastolic pressure (bottom number)
- 160 or higher systolic pressure
- 100 or higher diastolic pressure
The NHLBI defines prehypertension as:
- 120 to 139 systolic pressure
- 80 to 89 diastolic pressure
The NHLBI guidelines define normal blood pressure as follows:
- Less than 120 systolic pressure
- Less than 80 diastolic pressure
Treatment of high blood pressure
The treatment of high blood pressure is often attempted through the following methods:
- 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.