Chapter 2

Detecting High Blood Pressure

IN THIS CHAPTER

Getting an accurate reading

Measuring your blood pressure at home

Understanding the numbers

If you’ve ever had your blood pressure measured during a typical visit to your doctor’s office, it probably went something like this: You sat in the waiting room waiting for your appointment with your doctor. A nurse opened the door, called out your name, and hurriedly escorted you to the scale. You rushed to empty your pockets and take off your shoes before hopping on the scale. Then you were whisked back to the exam room and asked to sit on the exam table with your legs dangling. Your blood pressure was measured a couple minutes after you entered the exam room if not sooner. (Sometimes you can barely confirm your birth date before they have that blood pressure cuff around your arm.)

In this chapter, I explain why this approach isn’t likely to give you a proper measurement of your blood pressure. To diagnose high blood pressure accurately, you need to have your blood pressure measured correctly. In this chapter, I explain how to take your blood pressure the right way. Whether you’re taking your blood pressure at home or having it taken at your doctor’s office, the treatment regimen begins with an accurate blood pressure reading.

In this chapter, I also explain what the numbers mean and the newest guidelines regarding high blood pressure.

Looking at the Gauge Used to Measure Blood Pressure

In the olden days, we used a blood pressure gauge called a sphygmomanometer. It consisted of a cuff that went around your arm above the elbow. The bladder was the part of the cuff that filled with air. A tube connected the cuff to a column of mercury (that looks like an outdoor thermometer) at one end and a rubber bulb at the other. When the rubber bulb was squeezed, the air pressure in this closed system forced the column of mercury to rise as the bladder filled with air. Numbers along the column of mercury indicated how much pressure is present.

For years, the mercury blood pressure gauge was considered the gold standard for blood pressure measurement. But that’s not the case anymore. Today’s aneroid blood pressure cuffs are portable, with a small blood pressure gauge and bulb (see Figure 2-1).

An alternative blood pressure measurement instrument that is commonly used in medical offices, as well as for home blood pressure monitoring, is the oscillometric or automated blood pressure gauge.

As technology has advanced, so have the devices used to measure blood pressure. You may encounter some medical offices that use manual blood pressure cuffs to measure blood pressure, but many health professionals are now using automated blood pressure machines instead.

Don’t rely on blood pressure measurements you can get in supermarkets or pharmacies. They may not give you an accurate reading.

Taking Your Blood Pressure Correctly

Unlike the typical scenario I describe at the beginning of this chapter, where you’re rushed back to the exam room and you have your blood pressure taken almost immediately, a better scenario would go something like this: You sit in the waiting room waiting for your appointment with your doctor. A nurse opened the door, calls out your name, and escorts you to the scale and then to the exam room. You’re asked to sit in a chair with your feet flat on the floor (without your legs crossed). You’re told that your doctor will be with you in a few minutes, and you’re asked to relax and breathe deeply until then. The nurse may even turn off the lights and close the door so you can focus on your breath.

Sound too good be true? Maybe, but the point is that you should be seated in a chair, feet flat on the ground, legs uncrossed. Your back should be straight, and you should be as relaxed. Your blood pressure shouldn’t be taken as soon as you sit down.

Follow these few guidelines to get an accurate reading:

• Don’t smoke or drink alcohol or coffee within 30 minutes of a blood pressure measurement.
• Sit with your back and arm supported. Your supported elbow should be at about the level of your heart.
• Keep your feet on the ground.
• Rest for several minutes in that position before the measurement.
• Remain silent during the measurement.

When measuring blood pressure, it’s a good idea to know what the reading is in both arms. When repeating future blood pressure measurements, use the arm that has the higher blood pressure reading.

There should not be more than a 10- to 15-point difference between the blood pressures in both arms. If there is, your doctor may need to evaluate the arm with the lower blood pressure to make sure there is no narrowing or blockage of the blood flow in the arteries of that arm.

If you’ve been diagnosed with high blood pressure, you’ll need to take your blood pressure at home on a regular basis. This is especially important if you’re started a new blood pressure medication or if the dose or frequency of your medication has been changed. There are a number of advantages to measuring your own blood pressure at home:

• Frequent measurements of your blood pressure can tell you whether your treatment is working, and you can track your blood pressure at different times of the day.
• You can determine if your lifestyle changes (see Part 3) and/or medications are working. If they aren’t, you can alter the treatment long before your next office visit by getting in touch with your doctor.
• If your blood pressure remains steady and low, you may not have to see your doctor as frequently.

To use an automated blood pressure monitor at home, follow these steps:

1. Sit in a chair with your back straight and your feet on the floor (without your legs crossed).
2. Place the cuff over your arm about 1 inch above the bend of your elbow.

3. Close the cuff around your arm, sticking the Velcro ends together at the end of the cuff.

   If you have a large, muscular arm, that may cause an inaccurately high reading. Be sure to use a blood pressure gauge with a cuff that’s large enough to accommodate your arm.

4. Relax for about 5 minutes.

5. Place your arm at heart level (for example, lying straight out in front of you on a table or desk), and press the Start button on the machine.

   You’ll feel the cuff tighten around your arm, and then it will slowly loosen. It should beep or let you know when it’s done. (Read the instructions of your particular device to find out exactly how it works.)

Many automated blood pressure machines have an automatic electronic memory built in that will keep a record of your blood pressures. Check the manual of your blood pressure device to see for how long a time it stores the blood pressure readings. You may want to keep your own record on paper or using an app on your phone.

If you’re planning to buy an automated blood pressure cuff, make sure the device you buy is accurate. The American Medical Association has a website that lists devices that have been evaluated for accuracy. Just head to www.validatebp.org for more information.

Studies have shown that people who measure their own blood pressure are more likely to stay on a regimen for lowering their blood pressure. Measuring your blood pressure at home is important!