What Are High Blood Pressure and Prehypertension?
Blood pressure is the force of blood against the walls of arteries. Blood
pressure rises and falls during the day. When blood pressure stays elevated
over time, it is called high blood pressure.
The medical term for high blood pressure is hypertension. High blood pressure is dangerous because it makes
the heart work too hard and contributes to atherosclerosis (hardening of the arteries). It increases the risk of heart
disease and stroke, which are the first- and third-leading causes of death among Americans. High blood pressure also
can result in other conditions, such as congestive heart failure, kidney disease, and blindness.
A blood pressure level of 140/90 mmHg or higher is considered high. About two-thirds of people over age 65 have high
blood pressure. If your blood pressure is between 120/80 mmHg and 139/89 mmHg, then you have prehypertension. This
means that you don't have high blood pressure now but are likely to develop it in the future. You can take steps to
prevent high blood pressure by adopting a healthy lifestyle.
Those who do not have high blood pressure at age 55 face a 90 percent chance of developing it during their lifetimes.
So high blood pressure is a condition that most people have at some point in their lives.
Both numbers in a blood pressure test are important, but for people who are 50 or older, systolic pressure gives the
most accurate diagnosis of high blood pressure. Systolic pressure is the top number in a blood pressure reading.
It is high if it is 140 mmHg or above.
What is systolic blood pressure?
Systolic pressure is the force of blood in the arteries as the heart beats.
It is shown as the top number in a blood pressure reading. High blood pressure
is 140 and higher for systolic pressure. Diastolic pressure does not need to be high
for you to have high blood pressure. When that happens, the condition is called
"isolated systolic hypertension," or ISH.
Is isolated systolic high blood pressure common?
Yes. It is the most common form of high blood pressure for older
Americans. For most Americans, systolic blood pressure increases with age,
while diastolic increases until about age 55 and then declines. About 65
percent of hypertensives over age 60 have ISH. You may have ISH and feel fine.
As with other types of high blood pressure, ISH often causes no symptoms. To
find out if you have ISH or any type of high blood pressure see
your doctor and have a blood pressure test. The test is quick and painless.
Is isolated systolic high blood pressure dangerous?
Any form of high blood pressure is dangerous if not properly
treated. Both numbers in a blood pressure test are important, but, for some, the
systolic is especially meaningful. That's because, for those persons middle aged and
older, systolic pressure gives a better diagnosis of high blood
If left uncontrolled, high systolic pressure can lead to stroke, heart
attack, congestive heart failure, kidney damage, blindness, or other
conditions. While it cannot be cured once it has developed, ISH can be
Clinical studies have proven that treating a high systolic pressure saves
lives, greatly reduces illness, and improves the quality of life. Yet, most
Americans do not have their high systolic pressure under control.
Does it require special treatment?
Treatment options for ISH are the same as for other types of
high blood pressure, in which both systolic and diastolic pressures are high.
ISH is treated with lifestyle changes and/or medications. The key for any high
blood pressure treatment is to bring the condition under proper control. Blood
pressure should be controlled to less than 140/90 mmHg. If yours is not, then ask
your doctor why. You may just need a lifestyle or drug change, such as reducing
salt in your diet or adding a second medication.
What is diastolic blood pressure?
Diastolic pressure is the force of blood in the arteries as the heart
relaxes between beats. It's shown as the bottom number in a blood pressure
The diastolic blood pressure has been and remains, especially for younger people, an important hypertension number. The higher the diastolic blood pressure the greater the risk for heart attacks, strokes and kidney failure. As people become older, the diastolic pressure will begin to decrease and the systolic blood pressure begins to rise and becomes more important. A rise in systolic blood pressure will also increase the chance for heart attacks, strokes, and kidney failure. Your physician will use both the systolic and the diastolic blood pressure to determine your blood pressure category and appropriate prevention and treatment activities.
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