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). 

Blood tests may be done to assess risk factors for heart disease and stroke as well as looking for complications of hypertension. These include complete blood count (CBC), electrolytes, BUN (blood urea nitrogen), and creatinine and GFR (glomerular filtration rate) to measure kidney function. A fasting lipid profile will measure cholesterol and triglyceride levels in the blood. If appropriate, blood tests may be considered to look for an underlying cause of high blood pressure (secondary hypertension)including abnormal thyroid or adrenal gland function.
Blood tests may be done to assess risk factors for heart disease and stroke as well as looking for complications of hypertension. These include complete blood count (CBC), electrolytes, BUN (blood urea nitrogen), and creatinine and GFR (glomerular filtration rate) to measure kidney function. A fasting lipid profile will measure cholesterol and triglyceride levels in the blood. If appropriate, blood tests may be considered to look for an underlying cause of high blood pressure (secondary hypertension)including abnormal thyroid or adrenal gland function.
Lifestyle changes and medications can lower blood pressure and decrease the risk of health complications.[8] Lifestyle changes include weight loss, physical exercise, decreased salt intake, reducing alcohol intake, and a healthy diet.[5] If lifestyle changes are not sufficient then blood pressure medications are used.[8] Up to three medications can control blood pressure in 90% of people.[5] The treatment of moderately high arterial blood pressure (defined as >160/100 mmHg) with medications is associated with an improved life expectancy.[14] The effect of treatment of blood pressure between 130/80 mmHg and 160/100 mmHg is less clear, with some reviews finding benefit[7][15][16] and others finding unclear benefit.[17][18][19] High blood pressure affects between 16 and 37% of the population globally.[5] In 2010 hypertension was believed to have been a factor in 18% of all deaths (9.4 million globally).[9]
MRI (or magnetic resonance imaging) scan is a radiology technique which uses magnetism, radio waves, and a computer to produce images of body structures. MRI scanning is painless and does not involve X-ray radiation. Patients with heart pacemakers, metal implants, or metal chips or clips in or around the eyes cannot be scanned with MRI because of the effect of the magnet.
High blood pressure is classified as either primary (essential) high blood pressure or secondary high blood pressure.[5] About 90–95% of cases are primary, defined as high blood pressure due to nonspecific lifestyle and genetic factors.[5][6] Lifestyle factors that increase the risk include excess salt in the diet, excess body weight, smoking, and alcohol use.[1][5] The remaining 5–10% of cases are categorized as secondary high blood pressure, defined as high blood pressure due to an identifiable cause, such as chronic kidney disease, narrowing of the kidney arteries, an endocrine disorder, or the use of birth control pills.[5]

The authors bring several evidence-based yet progressive concepts into the guidelines, the first of which is that high blood pressure should be treated using a team approach. This makes sense, as science supports more and better patient education around self-monitoring, nutrition, and lifestyle changes, as well as stress management. Telehealth is emphasized as a cost-effective method of ongoing monitoring that is more convenient for patients than frequent office visits.
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SOURCES: The Journal of the American Medical Association, May 21, 2003. Aram Chobanian, MD, dean, Boston University School of Medicine and chair of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure. Claude Lenfant, MD, director of the National Heart, Lung, and Blood Institute (NHLBI) of the National Institutes of Health. Edward Roccella, PhD, MPH, coordinator of the National High Blood Pressure Education Program at NHLBI. John Laragh, MD, Cardiovascular Hypertension Center at New York Hospital/Cornell University Medical Center and editor-in-chief of the American Journal of Hypertension. WebMD Medical News: "Diuretics Best for High Blood Pressure."
Unlike high blood pressure symptoms, which are poorly defined and often totally absent, low blood pressure symptoms tend to be more upfront and easily recognizable. The development of symptoms is often a warning sign of a potentially serious underlying disorder. Generally speaking, your blood pressure would need to fall pretty dramatically before symptoms develop.
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