 A Better Life with Dr. Samjay Gupta. Do you know that almost half of all American adults have high blood pressure? That's defined as blood pressure at or above 130 over 80. Now if you're not sure what your numbers are, chances are you haven't had an annual physical exam. This is one of the most important vital signs you should know about your body because if you have high blood pressure, you're at higher risk for heart disease and stroke, two leading causes of death here in the United States.