On this page, the AHA lists health complications that may arise from having high blood pressure. High blood pressure may cause stroke, heart failure, vision loss, and kidney disease, among other things.
High blood pressure is often a problem, but low blood pressure can sometimes be an issue as well. Here, MedlinePlus describes when low blood pressure is considered an issue, the symptoms, and related conditions.
High blood pressure is often called the “silent killer” because it is not obvious when you have it. This page from the AHA provides information on recognizing the risks of high blood pressure and encourages high blood pressure awareness.