How Is Blood
Pressure Checked?
Having
your blood pressure checked is quick, easy, and painless.
Your blood pressure is measured with an instrument called
a sphygmomanometer (sfig’-mo-ma-nom-e-ter).
It works like this: A blood pressure cuff is wrapped around
your upper arm and inflated to stop the blood flow in
your artery for a few seconds. A valve is opened and air
is then released from the cuff and the sounds of your
blood rushing through the artery are heard through a stethoscope.
The first sound heard and registered on the gauge or mercury
column is the systolic blood pressure. It represents
the maximum pressure in the artery produced as the heart
contracts and the blood begins to flow. The last sound
heard as more air is released from the cuff is the diastolic
blood pressure. It represents the lowest pressure that
remains within the artery when the heart is at rest.
What
Do the Numbers Mean?
Blood pressure is always expressed in two numbers that
represent the systolic and diastolic pressures. These
numbers are measurements of millimeters (mm) of mercury
(Hg). The measurement is written one above or before the
other, with the systolic number on the top and the diastolic
number on the bottom. For example, a blood pressure measurement
of 120/80 mm Hg is expressed verbally as "120 over 80."
See the box below which show categories
for blood pressure levels in adults.
If your blood pressure is less than 140/90 mm Hg it is
considered normal. However, a blood pressure below 120/80
mm Hg is even better for your heart and blood vessels.
People use to think that low blood pressure (for example,
105/65 mm Hg in an adult) was unhealthy. Except for rare
cases, this is not true. High blood pressure or "hypertension"
is classified by stages and is more serious as the numbers
get higher.
|
Categories
For Blood Pressure Levels in Adults*
|
|
(Age
18 Years and Older)
|
Blood
Pressure Level (mm Hg) |
|
| Category |
Systolic |
Diastolic |
| Normal |
<130 |
<85 |
| High
Normal
|
130-139
|
85-89
|
| High
Blood Pressure |
|
|
| Stage
1 |
140-159 |
90-99 |
| Stage
2 |
160-179 |
100-109 |
| Stage
3 |
180-209 |
110-119 |
| Stage
4 |
>=210 |
>=120 |
*For
those not taking medicine for high blood pressure
and not having a short term serious illness.These
categories are from the National High Blood Pressure
Education Program.(<=less than>= greater than
or equal to)
|
What
Causes High Blood Pressure?
For most people, there is no single known cause of high
blood pressure. This type of high blood pressure is called
"primary" or "essential" hypertension. This type of blood
pressure can’t be cured, although in most cases it can
be controlled. That’s why it’s so important for everyone
to take steps to reduce their chances of developing high
blood pressure.
In a few people, high blood pressure can be traced to
known cause like tumors of the adrenal gland, chronic
kidney disease, hormone abnormalities, use of birth control
pills, or pregnancy. This is called " secondary hypertension."
Secondary hypertension is usually cured if its cause passes
or is corrected.
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