By Amy Norton
That figure is up sharply from what the American Heart Association (AHA) reported last year -- largely because of changes in the definition of high blood pressure. In 2017, guidelines lowered the threshold to 130/80 mm Hg, down from the long-used 140/90 mm Hg.
As a result, many more Americans now fall into the high blood pressure category.
In 2016, the new report estimates, about 48 percent of U.S. adults had some form of cardiovascular disease: That included 9 percent who had heart disease or were living with the aftereffects of a stroke. The rest had high blood pressure.
Dr. Emelia Benjamin led the committee that wrote the report, published online Jan. 31 in the AHA journal Circulation.
She said there's little doubt that high blood pressure is highly prevalent in the United States: the average American has about a 90 percent lifetime chance of developing the condition.
But there are plenty of steps people can take to delay or prevent high blood pressure, heart disease and stroke, said Benjamin, a professor at Boston University School of Medicine.
When it comes to exercise, she noted, "I'm not talking about training for the Boston Marathon. You can stop taking the elevator and use the stairs. You can park your car in the furthest spot from the store."
Focusing on simple, small steps may make lifestyle changes more attainable, Benjamin advised.
Based on the latest statistics, over 121 million Americans had some type of cardiovascular condition in 2016. That's up from 92 million in last year's AHA report.
The pervasiveness of that condition is a major concern, according to Dr. Ivor Benjamin, volunteer president of the AHA.
"As one of the most common and dangerous risk factors for heart disease and stroke, this overwhelming presence of high blood pressure can't be dismissed from the equation in our fight against cardiovascular disease," he said in an AHA statement.
He added that if high blood pressure were "eliminated," that would do more to cut deaths from heart disease and stroke than eliminating all other risk factors among women -- and all risk factors except smoking among men.
The AHA is reporting some encouraging trends, however.
Smoking rates among adults and teenagers continue to decline, while the number of people who exercise has continued to climb: Just under 27 percent of adults say they are sedentary, versus 40 percent back in 2005.
According to Benjamin, the report's author, "People are starting to get the message. If you go from being completely sedentary to even moderate activity, you'll benefit."
On the other hand, the prevalence of obesity remains stubbornly high, the AHA reported. Just under 40 percent of U.S. adults are obese, with almost 8 percent severely so. Meanwhile, over 18 percent of children and teenagers are obese.
There are no easy solutions to that problem, Benjamin noted. And the responsibility is not only on individuals, she said.
Many Americans lack access to affordable healthy food, safe places to exercise or health care, she explained -- and those are needs that have to be addressed.