The number of American adults with high blood pressure nearly doubled last week when the American College of Cardiology (ACA) and American Heart Association (AHA) released new guidelines and definitions for hypertension. Among the new guidelines is a checklist for taking blood pressure readings the right way.

Fortunately, the general population didn’t suddenly get sicker with the announcement last Tuesday. Rather, experts changed the guidelines for evaluating and managing one of the most common and dangerous conditions for American adults.

New definitions

Released last week, the new AHA/ACC guidelines lowered the threshold for Stage 1 hypertension to 130/80 mm Hg. This means that high blood pressure should be treated earlier with lifestyle changes and in some patients with medication.

Under previous definitions – last revised in 2003 – 1 of 3 US adults had high blood pressure. The new guidelines eliminate the category of “prehypertension,” bumping millions of adults up to Stage 1 hypertension. Nearly half (46 percent) of US adults are now categorized as having high blood pressure, with the greatest impact on young people. High blood pressure is expected to triple for men under age 45 and double for women under 45, according to the guidelines.

Nearly half (46 percent) of US adults are now categorized as having high blood pressure, with the greatest impact on young people.

Blood pressure categories under the new guidelines are:

  • Normal: Less than 120/80 mm Hg.
  • Elevated: Systolic between 120-129 and diastolic less than 80.
  • Stage 1: Systolic between 130-139 or diastolic between 80-89.
  • Stage 2: Systolic at least 140 or diastolic at least 90.
  • Hypertensive crisis: Systolic over 180 and/or diastolic over 120, with patients needing prompt changes in medication if there are no other indications of problems, or immediate hospitalization if there are signs of organ damage.

In addition to adjusting categories, the guidelines stress the importance of using proper technique to measure blood pressure. This includes suggestions regarding home blood pressure monitoring using validated devices and appropriate training of health care providers to reveal white-coat hypertension.

It’s all about risk

The goal of the new guidelines is to better align clinical practice with observable risk factors. High blood pressure increases the risk for heart disease and stroke, two of the leading causes of death for Americans.

At 130/80 “you’ve already doubled your risk of cardiovascular complications compared to those with a normal level of blood pressure,” explains Paul Whelton, MD, lead author for the guidelines. “We want to be straight with people – if you already have a doubling of risk, you need to know about it. It doesn’t mean you need medication, but it’s a yellow light that you need to be lowering your blood pressure, mainly with non-drug approaches.”

“We want to be straight with people – if you already have a doubling of risk, you need to know about it.”

A corresponding analysis suggests that the AHA/ACA guidelines have “the potential to increase hypertension awareness, encourage lifestyle modification and focus antihypertensive medication initiation and intensification on US adults with high CVD risk.”

How to read blood pressure the right way

Among the guidelines’ 481 pages is a checklist for accurate measurement of blood pressure. As NPR points out, the list includes many rules that health care providers are supposed to follow but which often get ignored.

The gap between guidelines and practice is easily illustrated from a patient perspective. These do’s and don’ts are aimed at making it less likely that you’ll get a reading that is falsely high, or low:

  • Do: Sit in a chair, feet flat on the ground, legs uncrossed, with your back supported and without talking, for at least five minutes before you get your blood pressure measured.
  • Don’t: Exercise, consume caffeine or smoke within 30 minutes of your test.
  • Do: Empty your bladder before your blood pressure is taken.
  • Don’t: Sit or lie on the exam table. Whelton says that can result in a falsely low blood pressure reading.
  • Do: Roll up your sleeve so the blood pressure cuff rests on bare skin, not clothing.
  • Don’t: Let your arm dangle or rest in your lap during the reading. It should be supported on a surface such as a desk.

As Whelton emphasizes in a recent interview at the annual AHA meeting, managing high blood pressure starts with having accurate information. “If we’re going to make decisions we need to have accurate measurement of blood pressure.”