Useless Medicine: Inaccurate Blood Pressure Readings

Research suggests that most readings taken in doctors’ offices are wrong

Physicians check blood pressure levels with a sphygmomanometer (an inflatable cuff attached to a gauge) and a stethoscope. But research suggests that four in five blood pressure readings taken in doctors’ offices are inaccurate.

Unfortunately, the lack of awareness of this very common and serious problem has turned millions of healthy individuals into erroneously diagnosed “patients.”

Most Medical Staff Don’t Follow Blood Pressure Testing Guidelines

Texas researchers enrolled patients with blood pressures higher than 120/80 and tested them according to the standard—but rarely followed—guidelines:

• Sitting in a chair with a back support
• Feet planted on the floor
• Legs uncrossed for five minutes
• No restrictive clothing
• No caffeine
• No exercise or tobacco for at least 30 minutes prior to testing

The tester made sure the cuff was sized and the arm placed appropriately, and two separate blood pressure readings were taken and averaged (plus a third if the first two varied by more than 5 mmHg).

The results were astounding. When these guidelines were followed, average systolic/diastolic pressures were 15.7/8.2 mmHg lower, going from 146.4/87.6 to 130.7/79.4.

These are significant differences, folks. The blood pressure classifications of 81 percent of the patients in this study improved—from stage 1 hypertension (140–159/90–99) to prehypertension (120–139/80–89) or from prehypertension to normal (less than 120/80).

Other Factors That Contribute to Inaccurate Blood Pressure Readings

This study is only one illustration of factors that contribute to faulty readings and over-diagnosis. Others include:

• Uncalibrated equipment
• “Interobserver reliability” (different nurses or doctors getting different results)
• White coat hypertension (elevation due to doctor-induced anxiety)

How to Ensure Accurate Blood Pressure Readings

There are two simple things you can do to ensure accurate blood pressure readings:

1. Insist that your blood pressure is taken properly (based on the guidelines outlined above)
2. For good measure, invest in a home monitor, learn how to use it correctly, and periodically take your blood pressure at home

Do not, I repeat, do not roll over and accept a diagnosis of hypertension until you have checked and double-checked your numbers.

More Dr. Whitaker Advice on Useless Medicine

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• Bypass surgery