Blood Pressure 101

Most of us know that "blood pressure" is an important indicator of health, but we may not know why. A quick look at what it is may help in understanding how it affects health and thus why it's important.

As the heart pumps blood out through the body, our blood vessels change slightly to help the blood move along. Each beat of the heart sends more blood into the arteries. This means that blood flow is not steady like a river but happens in small spurts. We can feel this spurting action throughout our bodies - our pulse measures how many times a minute the heart pumps out these spurts, and we can feel the pulse in every artery as the spurts pass through. The pulse shows that arteries expand very slightly with each heartbeat. This makes it easier for the heart to push out each spurt, and tiny muscles in the artery walls help to keep blood moving to even the remotest part of the body. In the fraction of a second that the heart rests between each beat, the arteries return to their normal size to be ready to move the next spurt.

OK, so what does that have to do with blood pressure? Blood pressure measures how easy or hard it is for the heart to move blood through the body. A blood pressure reading is made up of two numbers. The first is the systolic pressure, or how much force it takes the heart to push blood into the arteries. The second number is the diastolic pressure, or how much force the spurt of blood places against the artery wall in between heartbeats. The systolic number is always higher than the diastolic number, and blood pressure is stated as "systolic #" over "diastolic #" and written as "systolic #/diastolic#," for example, 120/80. A "normal" blood pressure is below 120/80.

Normal blood pressure: less than 120 less than 80 Prehypertension: 120-139 80-89 Hypertension: 140 or higher 90 or higher

A person is said to have high blood pressure (or hypertension) when the systolic pressure is 140 or higher or the diastolic pressure is 90 or higher. When either number is high, it means that the heart has to pump against resistance somewhere in the circulatory system. A few of the more frequent causes of resistance are: narrowing of blood vessels by fat and cholesterol plaques, hardening of blood vessel walls by plaque, a blood clot partially blocking a blood vessel, a backup of fluid in body tissues that compresses blood vessels, and certain illnesses and medications. High blood pressure is dangerous because the extra strain on the heart can cause heart failure; the increased likelihood of clots forming in the heart or blood vessels can cause heart attack or stroke; and kidneys and other organs, especially the eyes, can be damaged by decreased blood flow.

A person can have hypertension without knowing it - there are often no signs or symptoms. It is important for everyone, including children, to have their blood pressure checked at least once a year. Significant damage to the body can occur from undetected high blood pressure. A blood pressure between 120/80 and 139/89 is called prehypertension and also requires medical attention.

High blood pressure can run in families, but much of the time it is the result of overweight, an unhealthy diet, lack of exercise, another medical condition, or taking certain medications. About one in three adults in the U.S. has high blood pressure. People of any age can have it, but it is most common in people over age 65. In fact, after age 55 nine out of ten people will develop high blood pressure!

While hypertension can't be cured, it can be prevented or controlled. Since it's a lifestyle disease, many people can maintain or regain a normal blood pressure through behavior change:

• Lose weight and/or maintain a healthy weight
• Eat a healthy diet (reduced fat and calories, increase fruits, vegetables, and whole grains)
• Reduce salt (sodium) intake
• Stay or become physically active
• Drink alcohol only in moderation, if at all
• Don't use tobacco

If behavior change is not enough to lower high blood pressure, your doctor may prescribe medicine to help but not to replace healthy lifestyle choices. Behavior change is the essential first step and remains essential even when taking blood pressure medicine.

Ten Ways to Control Your High Blood Pressure Know your blood pressure. Have it checked regularly. Know what your weight should be. Keep it at or below that level. Don't use too much salt in cooking or at meals. Avoid salty foods. Eat a diet low in saturated fat according to American Heart Association recommendations. Control alcohol intake. Don't have more than one drink a day if you're a woman or two a day if you're a man. Take your medicine exactly as prescribed. Don't run out of pills even for a single day. Keep appointments with the doctor. Follow your doctor's advice about physical activity. Make certain your parents, brothers, sisters and children have their blood pressure checked regularly. Know that every step counts.

Visit the American Heart Association's website for a wealth of information, assistance, and news about achieving and maintaining a normal blood pressure.

See also:
Preventing High Blood Pressure
Preventing Stroke