What is high blood pressure?

In many people with high blood pressure, a single specific cause is not known. This is called essential or primary high blood pressure. Research is continuing to find causes. In some people, high blood pressure is the result of another medical problem or medication. When the cause is known, this is called secondary high blood pressure.
This section ? National Heart, Lung, and Blood Institute
What is high blood pressure? A blood pressure of 140/90 or higher is considered high blood pressure. Both numbers are important. If one or both numbers are usually high, you have high blood pressure. If you are being treated for high blood pressure, you still have high blood pressure even if you have repeated readings in the normal range. There are two levels of high blood pressure: Stage 1 and Stage 2 (see the chart below). Categories for Blood Pressure Levels in Adults* (In mmHg, millimeters of mercury)
Category
Systolic(Top number)
Diastolic(Bottom number)
Normal
Less than 120
Less than 80
Prehypertension
120-139
80-89
High Blood Pressure
Systolic
Diastolic
Stage 1
140-159
90-99
Stage 2
160 or higher
100 or higher* For adults 18 and older who:
Are not on medicine for high blood pressure
Are not having a short-term serious illness
Do not have other conditions such as diabetes and kidney disease Note: When systolic and diastolic blood pressures fall into different categories, the higher category should be used to classify blood pressure level. For example, 160/80 would be stage 2 high blood pressure. There is an exception to the above definition of high blood pressure. A blood pressure of 130/80 or higher is considered high blood pressure in persons with diabetes and chronic kidney disease.

What is Blood Pressure?

Blood is carried from the heart to all parts of your body in vessels called arteries. Blood pressure is the force of the blood pushing against the walls of the arteries. Each time the heart beats (about 60-70 times a minute at rest), it pumps out blood into the arteries. Your blood pressure is at its highest when the heart beats, pumping the blood. This is called systolic pressure. When the heart is at rest, between beats, your blood pressure falls. This is the diastolic pressure. Blood pressure is always given as these two numbers, the systolic and diastolic pressures. Both are important. Usually they are written one above or before the other, such as 120/80 mmHg. The top number is the systolic and the bottom the diastolic. When the two measurements are written down, the systolic pressure is the first or top number, and the diastolic pressure is the second or bottom number (for example, 120/80). If your blood pressure is 120/80, you say that it is "120 over 80." Blood pressure changes during the day. It is lowest as you sleep and rises when you get up. It also can rise when you are excited, nervous, or active. Still, for most of your waking hours, your blood pressure stays pretty much the same when you are sitting or standing still. That level should be lower than 120/80. When the level stays high, 140/90 or higher, you have high blood pressure. With high blood pressure, the heart works harder, your arteries take a beating, and your chances of a stroke, heart attack, and kidney problems are greater.
What causes it?In many people with high blood pressure, a single specific cause is not known. This is called essential or primary high blood pressure. Research is continuing to find causes. In some people, high blood pressure is the result of another medical problem or medication. When the cause is known, this is called secondary high blood pressure.

Exercise Reduces Blood Pressure...

people with high blood pressure, exercise can be the most important lifestyle change they can make, researchers say.
Yet two-thirds of doctors don't take the time to tell their patients with high blood pressure about the importance of exercise and physical activity, a new study finds.
"Patients do follow physician recommendations to exercise when instructed to, and patients who follow exercise recommendations tend to have lower systolic blood pressures than those who do not," said lead researcher Dr. Josiah Halm, a hypertension specialist at the University of Wisconsin School of Medicine and Public Health.
The findings are published in the summer issue of Ethnicity & Disease.
For the study, Halm's team collected data on 17,474 people who participated in the Third National Health and Nutrition Examination Survey. Among these people, 4,686 reported having high blood pressure.
The researchers found that only slightly more than one-third of the people with high blood pressure said their doctor had told them to increase physical activity as a way of bringing down their blood pressure.
Yet, 71 percent of patients with high blood pressure saw a drop in their blood pressure when they increased their physical activity, which means that they listened when doctors told them to exercise more, according to the report.
"Non-pharmacological methods such as exercising are important in improving blood pressure control on a population level as this study looked at the cross-section of the U.S. population," Halm said.
Studies have shown that small changes in blood pressure -- 2 to 3 mmHg -- could result in a 25 percent to 50 percent decrease in the incidence of high blood pressure, also known as hypertension, Halm said. "That would result in an annual reduction of stroke, coronary heart disease and all-cause mortality by 6 percent, 4 percent and 3 percent, respectively," he said.
Exercise -- as part of a comprehensive lifestyle-modification program including weight loss, low-salt diet, diets rich in fruits and vegetables and low in saturated fats -- has beneficial effects on blood pressure, Halm said.
"It is thus appropriate to recommend exercise as most patients will follow their physician recommendations and this is associated with improved blood pressure control and likely a reduction in the morbidity and mortality associated with uncontrolled blood pressure," he said.
Dr. Gregg C. Fonarow, a professor of cardiology at the University of California, Los Angeles, thinks more needs to be done to get patients to make lifestyle changes that will reduce their blood pressure.
"Despite clinical trial evidence and national guideline recommendations for exercise counseling to be provided for patients with high blood pressure, this study demonstrates that only one-third of these eligible patients received exercise counseling," he said.
"Much more needs to be done to ensure that patients with high blood pressure receive appropriate counseling on lifestyle change -- including counseling on the importance of regular aerobic exercise -- from their physicians," Fonarow said.