This fact about high blood pressure, or hypertension, may surprise you. According to the American Heart Association, about one in three American adults has it. That amounts to 75 million of us. Untreated, high blood pressure greatly raises the risk for heart disease and other serious conditions. Yet many of us tend to ignore it, because often, it presents no symptoms. Get your blood pressure checked occasionally, especially if there is a history of high blood pressure in your family.