Understanding High Blood Pressure -- the Basics
What Is High Blood Pressure?
High blood pressure, also known as hypertension, is the most common cardiovascular disease.
Blood pressure refers to the force of blood pushing against artery walls as it courses through the body. Like air in a tire or water in a hose, blood fills arteries to a certain capacity. Just as too much air pressure can damage a tire or too much water pushing through a garden hose can damage the hose, high blood pressure can threaten healthy arteries and lead to life-threatening conditions such as heart disease and stroke.
Hypertension is the leading cause of stroke and a major cause of heart attack. In the U.S. alone, more than 30% of American adults have high blood pressure.
If you have high blood pressure, you'll probably find out about it during a routine checkup. Or, you may have noticed a problem while taking your own blood pressure. Be sure to see your doctor for a definite diagnosis, and take the opportunity to learn what you can do to bring your blood pressure under control.
How Is Blood Pressure Measured?
A blood pressure reading appears as two numbers. The first and higher of the two is a measure of systolic pressure, or the pressure in the arteries when the heart beats and fills them with blood. The second number measures diastolic pressure, or the pressure in the arteries when the heart rests between beats.
Normal blood pressure rises steadily from about 90/60 at birth to about 120/80 in a healthy adult. If someone were to take your blood pressure immediately after you'd delivered a speech or jogged five miles, the reading would undoubtedly seem high. This is not necessarily cause for alarm: It's natural for blood pressure to rise and fall with changes in activity or emotional state.
It's also normal for blood pressure to vary from person to person, even from one area of your body to another. But when blood pressure remains consistently high, talk with your doctor about treatment. Consistently high blood pressure forces the heart to work far beyond its capacity. Along with injuring blood vessels, hypertension can damage the brain, eyes, and kidneys.
People with blood pressure readings of 140/90 or higher, taken on at least two occasions, are said to have high blood pressure. If the pressure remains high, your doctor will probably begin treatment. People with blood pressure readings of 180/120 or higher need treatment immediately. People at higher cardiovascular risk (such as diabetes, chronic kidney disease, or known heart and vascular disease) are treated if their blood pressure rises above 130/80, because they already have a high risk of heart disease.
Researchers identified people with blood pressures slightly higher than 120/80 as a category at high risk for developing hypertension. This condition is called pre-hypertension and affects an estimated 50 million American men and women. Pre-hypertension is now known to increase the likelihood of damage to arteries and the heart, brain, and kidneys, so many doctors are now recommending early treatment, though there is no evidence that this helps in the long run.