A new definition of high blood pressure (hypertension) :
(Please note that all numbers refer to mm Hg, or, millimeters of mercury.) The guidelines, in a nutshell, state that normal blood pressure is under 120/80, whereas before normal was under 140/90.
Now, elevated blood pressure (without a diagnosis of hypertension) is systolic blood pressure (the top number) between 120 and 129. That used to be a vague category called “prehypertension.”
Stage 1 high blood pressure (a diagnosis of hypertension) is now between 130 and 139 systolic or between 80 and 89 diastolic (the bottom number).
Stage 2 high blood pressure is now over 140 systolic or 90 diastolic.
The measurements must be obtained from at least two careful readings on at least two different occasions. What does careful mean? The guidelines provide a six-step tutorial on how, exactly, to correctly measure a blood pressure, which, admittedly, is sorely needed. My patients often have their first blood pressure taken immediately after they have rushed in through downtown traffic, as they’re sipping a large caffeinated beverage. While we always knew this could result in a falsely elevated measurement, it is now officially poor clinical technique resulting in an invalid reading.
New recommendations on monitoring blood pressure
The new guidelines also encourage additional monitoring, using a wearable digital monitor that continually takes blood pressure readings as you go about your life, or checked with your own cuff at home. This additional monitoring can help to tease out masked hypertension (when the blood pressure is normal in our office, but high the rest of the time) or white coat hypertension (when the blood pressure is high in our office, but normal the rest of the time). There are clear, helpful directions for setting patients up with a home blood pressure monitor, including a recommendation to give people specific instructions on when not to check blood pressure (within 30 minutes of smoking, drinking coffee, or exercising) and how to take a measurement correctly (seated comfortably, using the correct size cuff). The home blood pressure cuff should first be validated (checked in the office, for accuracy).
If you now have high blood pressure, you may not need medicines yet, The guidelines also outline very clearly when a diet-and-lifestyle approach is the recommended, first-line treatment, and when medications are simply just what you have to do. Thankfully, the decision is largely based on facts and statistics. For the elevated blood pressure category, medications are actually not recommended; rather, a long list of evidence-based, non-drug interventions are. What are these interventions? Things that really work: a diet high in fruits and vegetables (such as the DASH diet, which is naturally high in potassium); decreased salt and bad fats; more activity; weight loss if one is overweight or obese; and no more than two alcoholic drinks per day for men, and one for women. Simply changing what you eat can bring down systolic blood pressure by as much as 11 points, and each additional healthy habit you adopt can bring it down another four to five points.
For people with stage 1 hypertension who don’t have cardiovascular disease and are at low risk for developing it (less than 10% risk of an event within 10 years), lifestyle changes are still the way to go. (Risk is determined using a well-researched, widely used formula available here.)
However, if a patient has any kind of cardiovascular disease and stage 1 hypertension (a blood pressure over 130 systolic or 80 diastolic), or no existing cardiovascular disease but a significant risk of developing it (over 10% risk within the next 10 years), then lifestyle changes plus medications are recommended. And, even if someone has less than a 10% risk, if their blood pressure is over 140 systolic or 90 diastolic, which is now stage 2 high blood pressure, they ought to be treated with medication as well.