High Blood Pressure Hypertension (cont.)

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How is blood pressure measured?

Blood pressure is measured by a blood pressure cuff (sphygmomanometer). The blood pressure cuff consists of an air pump, a pressure gauge, and a rubber cuff. The instrument measures the blood pressure in units called millimeters of mercury (mm Hg).

The cuff is placed around the upper arm and inflated with an air pump to a pressure that blocks the flow of blood in the main artery that travels through the arm. The arm is held at the side of the body at the level of the heart, and the pressure of the cuff is gradually released. As the pressure decreases, a health practitioner listens with a stethoscope over the artery at the front of the elbow or an electronic machine senses the pulsation. The pressure at which the practitioner (or machine) first hears a pulsation from the artery is the systolic pressure (the top number). As the cuff pressure decreases further, the pressure at which the pulsation finally stops is the diastolic pressure (the bottom number).

What do blood pressure readings mean?

Blood pressure readings can vary in a single person throughout the day depending on the situation. Factors such as stress, anxiety, foods eaten (caffeine or salt intake), smoking, or exercise can cause pressure to rise.

The American Heart Association defines a normal blood pressure as less than 120/80. Pre-hypertension ranges between 120/80 and 139/89, and high blood pressure is 140/90 and higher. In pregnancy normal blood pressure should be below 120/80.

If your blood pressure reaches into the high range, you should see your doctor about lifestyle modification and possibly medication especially if you have other risk factors, such as diabetes or heart disease.

High blood pressure (for example, 180/110 or higher) may indicate an emergency situation. If this high blood pressure is associated with chest pain, shortness of breath, headache, dizziness, or back or abdominal pain, seek medical care immediately. If you are experiencing no associated symptoms with a high blood pressure reading such as this, re-check it again within a few minutes and contact your doctor or go to an emergency room if it is still high.

If your blood pressure is lower than about 100/60 you may have low blood pressure, depending on the associated symptoms. If you are unsure, check with your doctor.

Medically Reviewed by a Doctor on 2/18/2014

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