By Alice Park -TIME Health
In the first change to blood pressure guidelines in 14 years, the American Heart Association and the American College of Cardiology say that the threshold for high blood pressure should be lower. Under the new guidelines, nearly half of American adults will be considered to have high blood pressure, according to the heart experts who wrote them.
Until now, recommendations have set 140/90 mmHg as the threshold for high blood pressure. The new guidelines say readings above 130/80 mmHg are considered high. Normal blood pressure is less than 120/80 mmHg.
The change comes after several years of evolving research on blood pressure and its health consequences. High blood pressure can stress vessels and cause them to be less elastic, which can increase the risk of heart disease and stroke. Hypertension is second only to smoking as a leading cause of heart disease deaths.
“We now have clear enough data that lower blood pressure really does reduce cardiovascular events,” says Dr. Eugenia Gianos, co-clinical director of the center for the prevention of cardiovascular disease at NYU Langone Health. (Gianos was not involved in the writing the guidelines.)
In a study published in 2015, researchers compared people who maintained their blood pressure at 140/90 to those who followed a lower target of 120/80. They found that the lower the blood pressure, the better the health outcomes. People with lower readings had less premature heart-related deaths, as well as deaths from any cause.
Under the older, higher target, 32% of adults in the U.S. had hypertension. With the new guidelines, 46% of Americans have high blood pressure.
But even though more people may be considered to have high blood pressure, not all of them will require medications to treat it, doctors say. The guidelines suggest that for many people, making changes in lifestyle—such as improving the diet to lower salt intake and increasing physical activity—can bring levels down to the new, lower range. People should only consider taking anti-hypertensive medications if these efforts don’t work, the guidelines say.
Based on the results of the large 2015 study, many doctors have already advised their patients — especially people with risk factors for heart disease, like being smokers, being overweight or having type 2 diabetes— to bring their blood pressure below 140/90. While some people may be concerned to learn they now have high blood pressure, Gianos says that the new guidelines are a sign that experts are learning and improving their advice to people in order to further lower their risk of dying from heart-related causes.