Dear Doctors: I want to start checking my blood pressure to see if the high readings my doctor gets are accurate. I read you should always sit still before getting a reading. Is that true? That never happens at my doctor's office.
Dear Reader: Blood pressure has been central to several columns in recent months. It's an important metric when it comes to general health, so we will risk repeating ourselves a bit in this new discussion.
Blood pressure readings measure the force that circulating blood exerts on the walls of the arteries. The two numbers, expressed as a fraction, show the degree and the range of the force. The top number is systolic pressure. That's blood pressure as the heart contracts. The bottom number, known as diastolic pressure, reflects blood pressure while the heart is at rest.
Blood pressure varies throughout the day. Readings are affected by activity, physical fitness, illness, stress, emotion, salt intake and even time of day. Getting an accurate picture of your blood pressure profile requires both proper technique and multiple readings. To aid in that, you need a good monitor. A list of at-home monitors that meet the American Heart Association's criteria is available at validateBP.org. Your doctor can also advise you on a choice.
When taking blood pressure, make sure it has been at least 30 minutes since you used tobacco or caffeine or engaged in exercise. Empty your bladder, as that can affect readings. Sit upright, your back supported, with both feet flat on the floor. The arm on which you place the cuff should be relaxed and supported at the level of your heart. The cuff itself should be firmly in place, but not tight. You should be able to slip a fingertip beneath the top of the cuff. The bottom of the cuff sits directly above the bend of the inner elbow, with the air tubes centered.
Begin by taking about five minutes to sit quietly. Let it be a meditative pause. Don't chat or watch TV or read your phone while you wait. Most devices are automated and digital. When you’re ready, press the start button. The cuff will inflate, pause for a moment, then gradually deflate. Be sure to stay relaxed and breathe normally as the machine goes through its cycle. The final reading is displayed on the monitor in the familiar fraction format.
As we mentioned, blood pressure is not a constant. Don't panic if you get an occasional high reading. For the most accurate blood pressure profile, you need multiple readings. It is recommended these be taken at the same time each day, perhaps twice in the morning and twice in the afternoon. Over the course of a week, with multiple readings, you'll get a fuller picture than a single reading can offer.
At this time, 120/80 falls into the normal range. Blood pressure higher than 130/80 enters the realm of hypertension. If your readings prove consistently high, it's a good idea to review the results with your doctor.
(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10960 Wilshire Blvd., Suite 1955, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)
