Health care providers measure blood pressure with a sphygmomanometer (sfig-mo-muh-NAH-muh-ter), which has a cuff that's wrapped around the upper arm and pumped up to create pressure. When the cuff is inflated, it squeezes a large artery in the arm, stopping the blood flow for a moment. Blood pressure is measured as air is gradually let out of the cuff, which allows blood to flow through the artery again.
^ Martin-Cabezas, Rodrigo; Seelam, Narendra; Petit, Catherine; Agossa, Kévimy; Gaertner, Sébastien; Tenenbaum, Henri; Davideau, Jean-Luc; Huck, Olivier (October 2016). "Association between periodontitis and arterial hypertension: A systematic review and meta-analysis". American Heart Journal. 180: 98–112. doi:10.1016/j.ahj.2016.07.018. ISSN 1097-6744. PMID 27659888.
If your blood pressure is above the normal range for up to 5 readings (taken at different visits), your doctor will likely diagnose you with high blood pressure. Sometimes the doctor may diagnose you after a fewer number of readings, depending on how high above normal your blood pressure is and if you have other medical conditions. Blood pressure tends to be at its highest during exercise, physical work, or stress, and lowest during sleep. Everyone can have a temporary increase in blood pressure at one time or another, which is why it's important to take multiple readings.
Sodium is a key part of how the body controls blood pressure levels. The kidneys help balance fluid and sodium levels in the body. They use sodium and potassium to remove excess fluid from the blood. The body gets rid of this excess fluid as urine. When sodium levels in the blood are high, blood vessels retain more fluid. This increases blood pressure against the blood vessel walls.
In the 19th and 20th centuries, before effective pharmacological treatment for hypertension became possible, three treatment modalities were used, all with numerous side-effects: strict sodium restriction (for example the rice diet[152]), sympathectomy (surgical ablation of parts of the sympathetic nervous system), and pyrogen therapy (injection of substances that caused a fever, indirectly reducing blood pressure).[152][158] 

Moderate or severe bleeding can quickly deplete an individual's body of blood, leading to low blood pressure or orthostatic hypotension. Bleeding can result from trauma, surgical complications, or from gastrointestinal abnormalities such as ulcers, tumors, or diverticulosis. Occasionally, the bleeding may be so severe and rapid (for example, bleeding from a ruptured aortic aneurysm) that it causes shock and death rapidly.
A person consistently showing blood pressure higher than 140/90 over several readings is considered to have hypertension. Doctors advise these people to make effective lifestyle changes to help lower their blood pressure, such as maintaining a healthy weight, including exercise in their daily routine, limiting salt and alcohol intake, and quitting smoking. The doctors will also recommend medication for hypertension depending on how much higher the BP is as compared to the normal blood pressure range and any other health problems that the patient faces.

Blood pressure is expressed by two measurements, the systolic and diastolic pressures, which are the maximum and minimum pressures, respectively.[1] For most adults, normal blood pressure at rest is within the range of 100–130 millimeters mercury (mmHg) systolic and 60–80 mmHg diastolic.[7][12] For most adults, high blood pressure is present if the resting blood pressure is persistently at or above 130/80 or 140/90 mmHg.[5][7] Different numbers apply to children.[13] Ambulatory blood pressure monitoring over a 24-hour period appears more accurate than office-based blood pressure measurement.[5][10]

^ Jump up to: a b c d e National High Blood Pressure Education Program Working Group on High Blood Pressure in Children and Adolescents (August 2004). "The fourth report on the diagnosis, evaluation, and treatment of high blood pressure in children and adolescents". Pediatrics. 114 (2 Suppl 4th Report): 555–76. doi:10.1542/peds.114.2.S2.555. PMID 15286277.
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.

Rates of high blood pressure in children and adolescents have increased in the last 20 years in the United States.[147] Childhood hypertension, particularly in pre-adolescents, is more often secondary to an underlying disorder than in adults. Kidney disease is the most common secondary cause of hypertension in children and adolescents. Nevertheless, primary or essential hypertension accounts for most cases.[148]
Blood pressure is measured with a blood pressure cuff (sphygmomanometer). This may be done using a stethoscope and a cuff and gauge or by an automatic machine. It is a routine part of the physical examination and one of the vital signs often recorded for a patient visit. Other vital signs include pulse rate, respiratory rate (breathing rate), temperature, and weight.
Pulse pressure (the difference between systolic and diastolic blood pressure) is frequently increased in older people with hypertension. This can mean that systolic pressure is abnormally high, but diastolic pressure may be normal or low a condition termed isolated systolic hypertension.[59] The high pulse pressure in elderly people with hypertension or isolated systolic hypertension is explained by increased arterial stiffness, which typically accompanies aging and may be exacerbated by high blood pressure.[60]
Some people may ask why doctors are lowering the threshold for high blood pressure, when it was already difficult for many patients to achieve the previous blood pressure targets of below 140 mm Hg/90 mm Hg, said Dr. Pamela B. Morris, a preventive cardiologist and chairwoman of the ACC's Prevention of Cardiovascular Disease Leadership Council. However, Morris said that the guidelines were changed because "we now have more precise estimates of the risk of [high] blood pressures," and these new guidelines really communicate that risk to patients. So, just because it's going to be difficult for people to achieve, "I don't think it's a reason not to communicate the risk to patients, and to empower them to make appropriate lifestyle modifications," Morris told Live Science.
There is no treatment available for the causes of portal hypertension. However, treatment can prevent or manage the complications. Diet, medication (nonselective beta-blockers), endoscopic therapy, surgery, and radiology procedures can all help in treating or preventing symptoms of portal hypertension. If these treatments are unsuccessful in treating symptoms, transjugular intrahepatic portosystemic shunt (TIPS) or distal splenorenal shunt (DSRA) are two procedures that may reduce pressure in the portal veins. Maintaining a healthy lifestyle may help to prevent portal hypertension.
To control or lower high blood pressure, your doctor may recommend that you adopt heart-healthy lifestyle changes, such as heart-healthy eating patterns like the DASH eating plan, alone or with medicines. Controlling or lowering blood pressure can also help prevent or delay high blood pressure complications, such as chronic kidney disease, heart attack, heart failure, stroke, and possibly vascular dementia.
The symptoms similar to symptoms of patients with hypertensive crisis are discussed in medieval Persian medical texts in the chapter of "fullness disease".[155] The symptoms include headache, heaviness in the head, sluggish movements, general redness and warm to touch feel of the body, prominent, distended and tense vessels, fullness of the pulse, distension of the skin, coloured and dense urine, loss of appetite, weak eyesight, impairment of thinking, yawning, drowsiness, vascular rupture, and hemorrhagic stroke.[156] Fullness disease was presumed to be due to an excessive amount of blood within the blood vessels.
If your blood pressure remains high for a long period of time, you run the risk of damaging your blood vessels. Your stroke risk rises significantly, too. And because your heart is working harder to push blood through your system, that very valuable muscle can become overworked and grow thicker. An enlarged heart causes further complications, including heart failure. Medications and special implantable pumps can help boost heart function. But if you can manage your blood pressure before it gets too high and puts your heart at risk, you may be able to avoid a lot of complications down the road.

Blood pressure readings fall into four general categories, ranging from normal to stage 2 high blood pressure (hypertension). The level of your blood pressure determines what kind of treatment you may need. To get an accurate blood pressure measurement, your doctor should evaluate your readings based on the average of two or more blood pressure readings at three or more office visits.