High blood pressure is classified as either primary (essential) high blood pressure or secondary high blood pressure. About 90–95% of cases are primary, defined as high blood pressure due to nonspecific lifestyle and genetic factors. Lifestyle factors that increase the risk include excess salt in the diet, excess body weight, smoking, and alcohol use. 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.
"Blood pressure guidelines are not updated at regular intervals. Instead, they are changed when sufficient new evidence suggests the old ones weren't accurate or relevant anymore," says Dr. Paul Conlin, an endocrinologist with Harvard-affiliated VA Boston Healthcare System and Brigham and Women's Hospital. "The goal now with the new guidelines is to help people address high blood pressure — and the problems that may accompany it like heart attack and stroke — much earlier."
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.
Secondary hypertension results from an identifiable cause. Kidney disease is the most common secondary cause of hypertension. Hypertension can also be caused by endocrine conditions, such as Cushing's syndrome, hyperthyroidism, hypothyroidism, acromegaly, Conn's syndrome or hyperaldosteronism, renal artery stenosis (from atherosclerosis or fibromuscular dysplasia), hyperparathyroidism, and pheochromocytoma. Other causes of secondary hypertension include obesity, sleep apnea, pregnancy, coarctation of the aorta, excessive eating of liquorice, excessive drinking of alcohol, and certain prescription medicines, herbal remedies, and illegal drugs such as cocaine and methamphetamine. Arsenic exposure through drinking water has been shown to correlate with elevated blood pressure.
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.
People with stage 1 hypertension who don't meet these criteria should be treated with lifestyle modifications. These include: starting the "DASH" diet, which is high in fruit, vegetables and fiber and low in saturated fat and sodium (less than 1,500 mg per day); exercising for at least 30 minutes a day, three times a week; and restricting alcohol intake to less than two drinks a day for men and one drink a day for women, said vice chairman of the new guidelines, Dr. Robert Carey, a professor of medicine and dean emeritus at the University of Virginia Health System School of Medicine. [6 Healthy Habits Dramatically Reduce Heart Disease Risk in Women]
First, we collect and analyze statewide data using telephone surveys, hospital information, and death certificates, so we are able to know which groups of people are experiencing hypertension and the impacts of uncontrolled high blood pressure. This includes looking at geography, age, racial/ethnic status, education levels, and other demographic information. When the data is compiled, we make it available on the DOH web site. We estimate that in 2015, nearly 14,000 deaths and 71,000 hospitalizations were due to heart disease and stroke.
Blood pressure is assessed using two parameters -- the systolic and diastolic pressures -- which measure, respectively, the maximum pressure exerted in the arteries as the heart contracts, and the minimum pressure in those vessels between cardiac contractions. In adults, blood pressure is considered normal if the top number (systolic pressure) is between 90 and 120 and the bottom number (diastolic) is between 60 and 80.
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If your blood pressure is 120/80 millimeters of mercury (mm Hg) or lower, it’s considered normal. Generally, if the blood pressure reading is under 90/60 mm Hg, it is abnormally low and is referred to as hypotension. Some adults regularly have a blood pressure in the hypotensive range, but have no symptoms at all and do not require treatment. In serious cases, though, hypotension can result in a decreased supply of oxygen and nutrients to your brain, which can eventually lead to life-threatening shock.
Much is being made of the fact that the new definitions of high blood pressure will mean roughly half of all US citizens will be considered to have high blood pressure, but when you really look at the numbers, as cardiologists already have, not that many more people will actually be advised to take medications. Although the public has good reason to be suspicious of “big pharma,” that’s not what this is about.
The new guidelines note that blood pressure should be measured on a regular basis and encourage people to use home blood pressure monitors. Monitors can range from $40 to $100 on average, but your insurance may cover part or all of the cost. Measure your blood pressure a few times a week and see your doctor if you notice any significant changes. Here are some tips on how to choose and use a monitor.
On physical examination, hypertension may be associated with the presence of changes in the optic fundus seen by ophthalmoscopy. The severity of the changes typical of hypertensive retinopathy is graded from I to IV; grades I and II may be difficult to differentiate. The severity of the retinopathy correlates roughly with the duration or the severity of the hypertension.