What is High Blood Pressure
Parish Nursing
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What is blood pressure?
Blood is carried from the heart to all parts of your body in vessels called
arteries. Blood pressure is the force of the blood pushing against the
walls of the arteries. Each time the heart beats (about 60-70 times a
minute at rest), it pumps out blood into the arteries. Your blood
pressure is at its highest when the heart beats, pumping the blood.
This is called systolic pressure. When the heart is at rest, between
beats, your blood pressure falls. This is the diastolic pressure.
Blood pressure is always given as these two numbers, the systolic and diastolic
pressures. Both are important. Usually they are written one above or before the
other, such as 120/80 mmHg. The top number is the systolic and the bottom the
diastolic. When the two measurements are written down, the systolic pressure is
the first or top number, and the diastolic pressure is the second or bottom
number (for example, 120/80). If your blood pressure is 120/80, you say that it is "120 over 80."
Blood pressure changes during the day. It is lowest as you sleep and rises when you get up.
It also can rise when you are excited, nervous, or active.
Still, for most of your waking hours, your blood pressure stays pretty much
the same when you are sitting or standing still. That level should be lower
than 120/80. When the level stays high, 140/90 or higher, you have high blood
pressure. With high blood pressure, the heart works harder, your arteries take
a beating, and your chances of a stroke, heart attack, and kidney problems are greater.
What is normal blood pressure?
A blood pressure reading below 120/80 is considered normal. In general, lower is
better. However, very low blood pressures can sometimes be a cause for concern
and should be checked out by a doctor.
Doctors classify blood pressures under 140/90 as either "normal," or "prehypertension."
"Normal" blood pressures are lower than 120/80.
"Prehypertension" is blood pressure between 120 and 139 for the top number, or
between 80 and 89 for the bottom number. For example, blood pressure readings of
138/82, 128/89, or 130/86 are all in the "prehypertension" range. If your blood
pressure is in the prehypertension range, it is more likely that you will end up
with high blood pressure unless you take action to prevent it.
What is high blood pressure?
A blood pressure of 140/90 or higher is considered high blood pressure. Both
numbers are important. If one or both numbers are usually high, you have high
blood pressure. If you are being treated for high blood pressure, you still
have high blood pressure even if you have repeated readings in the normal range.
There are two levels of high blood pressure: Stage 1 and Stage 2 (see the chart below).
Categories for Blood Pressure Levels in Adults*
(In mmHg, millimeters of mercury)
| Category |
Systolic
(Top number) |
Diastolic
(Bottom number) |
| Normal |
Less than 120 |
Less than 80 |
| Prehypertension |
120-139 |
80-89 |
|
|
|
| High Blood Pressure |
Systolic |
Diastolic |
| Stage 1 |
140-159 |
90-99 |
| Stage 2 |
160 or higher |
100 or higher |
* For adults 18 and older who:
Are not on medicine for high blood pressure
Are not having a short-term serious illness
Do not have other conditions such as diabetes and kidney disease
Note: When systolic and diastolic blood pressures fall into different
categories, the higher category should be used to classify blood pressure
level. For example, 160/80 would be stage 2 high blood pressure.
There is an exception to the above definition of high blood pressure.
A blood pressure of 130/80 or higher is considered high blood pressure in
persons with diabetes and chronic kidney disease.