What is blood pressure?
Blood pressure is a measure of the force of blood against the walls of your arteries (or blood vessels) as blood flows through the body. Blood pressure is given as two numbers. The first or top number is the systolic pressure—the pressure of the blood in the vessels as the heart beats. The second or bottom number is the diastolic pressure—the pressure in the vessels as the heart relaxes between beats. Blood pressure is measured in millimeters of mercury (mm Hg), reflecting how much the pressure in your arteries would raise a column of mercury. A blood pressure of 120 mm Hg systolic and 80 mm Hg diastolic is written 120/80 (“120 over 80”).
Blood Pressure Categories
|Classification of Blood Pressure For Adults1|
|Category||Systolic (mm Hg)||Diastolic (mm Hg)|
|Normal||Less than 120||and||Less than 80|
|Stage 1 High BP||140-159||or||90-99|
|Stage 2 High BP||160 or higher||or||100 or higher|
What is high blood pressure?
Normal blood pressure is less than 120 mm Hg systolic and 80 mm Hg diastolic. For adults, high blood pressure ( hypertension) is when blood pressure is higher than 140 mm Hg systolic and/or 90 mm Hg diastolic. High blood pressure is dangerous because it makes the heart work too hard and leads to hardening of the arteries, increasing your risk of heart disease and stroke
What is prehypertension?
If your blood pressure is higher than 120/80 but lower than 140/90, you have prehypertension. This means that you don't have high blood pressure yet, but are very likely to develop it in the future.
How does high blood pressure affect heart disease risk?
High blood pressure increases your risk of dying early or having a heart attack, stroke, or heart failure. For each rise in blood pressure of 20 mm Hg systolic (top) or 10 mm Hg diastolic (bottom), your risk of heart disease doubles. It is estimated that controlling blood pressure could prevent one third of heart disease problems in women.10 Women and men with high blood pressure at age 50 develop heart disease 7 years earlier and die on average 5 years earlier than people with normal blood pressure at this age.11
High blood pressure damages your heart in a number of ways. It can cause your heart to become enlarged as a result of being overworked. Eventually, the heart gets weaker and cannot pump blood as effectively through your body. An enlarged, thickened heart can cause irregular heart beats ( arrhythmia). High blood pressure also contributes to the buildup of fatty plaque in the arteries. It makes your arteries stiffer and less flexible, making it harder for blood to flow through them easily.
High blood pressure that is not controlled affects not only your heart and blood vessels, but other organs as well. It can cause impaired vision and blindness, and kidney damage that may require dialysis or a kidney transplant.
What is " white coat hypertension"?
Many people become anxious when visiting their healthcare provider, causing their blood pressure to temporarily rise. This condition is called white coat hypertension (the name refers to the white coats that doctors usually wear) and is more common in women than men.2
If your healthcare provider thinks you may have white coat hypertension, you may be asked to wear a device called an ambulatory blood pressure monitor, or Holter monitor. It is usually worn for 24 hours in order to see what your blood pressure is like outside of the hospital, office, or clinic and in a more relaxed environment.
Women with white coat hypertension are not at the same increased risk for heart disease as women with traditional high blood pressure.3, 4 However, they may have a slightly higher risk than women who don't have white coat hypertension.5
What other types of hypertension are there?
Many older people develop a form of high blood pressure called isolated systolic hypertension (ISH). This occurs when the top (systolic) number is high but the bottom (diastolic) number is normal.
There are also specific types of high blood pressure that can develop during pregnancy (gestational hypertension and preeclampsia) that are risky for both the mother and baby, and require careful monitoring and treatment. However, these conditions do not increase the risk of heart disease or stroke.