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WHAT IS BLOOD PRESSURE
Blood pressure is the force exerted by blood on the walls of blood vessels (arteries). When the heart pumps blood into the arteries, the pressure is called systolic pressure. On the other hand, the force with which the arteries resist the flow of the blood from the heart is called diastolic pressure. To say in other words, systolic pressure is when the heart beats, and diastolic pressure is when the heart relaxes between the beats, and the blood pumped by the heart travels through the blood vessels in the body. Blood pressure is measured into milligrams of mercury (mmHg). In a blood pressure reading of 140/90, for example, the upper number 140 is called systolic blood pressure, and the lower number 90 is called diastolic blood pressure.

WHAT IS HIGH BLOOD PRESSURE
When blood exerts more than the normal force on the walls of the arteries, the pressure is called high blood pressure. According to the current standard, a blood pressure reading of 140/90 or greater is classified as high blood pressure, whereas a reading of 120/80 is classified as prehypertension. (Prehypertension is a condition in which blood pressure is yet not so high as to be classified as high blood pressure but will change into it if healthy lifestyle changes are not made.)

CLASSIFICATION OF BLOOD PRESSURE
Currently, blood pressure in adults is classified into three main categories:

SYMPTOMS OF HIGH BLOOD PRESSURE
High blood pressure generally has no signs, and yet it is dangerous; this is why it is called a “silent killer.” When high blood pressure is severe, or remains untreated for long, it causes symptoms such as nausea, vomiting, fatigue, restlessness, dizziness, and shortness of breath. These symptoms appear late when high blood pressure has already caused some damage to the heart, brain, and kidneys. Highblood pressure when severe, may cause swelling in the brain, making you drowsy or unconscious.

CAUSE OF HIGH BLOOD PRESSURE
High blood pressure can be essential (primary) or secondary. The specific cause of essential high blood pressure is not known, whereas the cause of secondary high blood pressure can be identified. Essential high blood pressure is the most common form of high blood pressure, occurring in more than 90 percent of patients, including people with type 2 diabetes. Heredity, obesity, body’s resistance to the action of insulin, low levels of nitric oxide (this substance keeps blood vessels relaxed), and low birth weights are suspected to cause essential high blood pressure. Causes of secondary high blood pressure are identifiable. These may include such medical conditions as hardening of the arteries (see Part 5) in which the heart has to use greater force to pump the blood through clogged arteries, kidney disease, and liver disease. Also, long-term use of nonsteroidal and anti-inflammatory drugs (NSAID) such as diclofenac (Voltaren) and ibuprofen (Advil), oral contraceptive pills, nasal decongestants, appetite suppressants, alcohol consumption, tobacco smoking, taking coffee in excess, stress, and exposure to lead even at low levels, can contribute to high blood pressure.

EFFECTS OF HIGH BLOOD PRESSURE
Your arteries, due to constant exposure to high blood pressure, can become injured and scarred. When the arteries are injured, cholesterol and fat circulating in the blood tend to pile up on the site of injury. The fat and cholesterol deposits tend to clog the arteries, making them hard and narrow. As a result, the heart has to work hard to pump the blood through clogged arteries, a condition that raises blood pressure. When this condition continues for long, the heart gets enlarged and becomes weak. A weak heart cannot pump enough blood, and, as a result, blood flow to various parts of the body is decreased. When the affected organs of the body do not get enough supply of the blood, they become weak, damaged, and their functions are impaired. Long-standing high blood pressure contributes to serious organ damage, including heart attack, stroke, kidney failure, and eye damage.

THE RIGHT WAY TO MEASURE BLOOD PRESSURE
Blood pressure should be measured with a blood pressure instrument using mercury (sphygmomanometer)or a non-mercury device giving correct readings. For correct measurement of your blood pressure:

• Sit down on a chair comfortably for at least 5 minutes before your blood pressure is measured. Your feet should be on the floor and not hanging as at an examination table in a doctor’s office.

• Refrain from smoking and taking tea and coffee about 30 minutes before measuring blood pressure.

• You should not be taking blood pressure-lowering medication when blood pressure is measured for diagnosing high blood pressure.

• Use a blood pressure measuring cuff of appropriate size (not too loose or too tight); your arm should be supported at your heart level.

• Blood pressure should be measured in both the arms; if readings are different, the higher value should be used for diagnosis.

• Two or more readings separated by 2 minutes should be averaged to estimate your blood pressure.

• To detect any abnormal fall in blood pressure such as when you rise from a sitting position to a standing position your blood pressure should be periodically checked in a standing position also.