This document defines blood pressure, discusses the different categories of blood pressure in adults, explains how blood pressure is detected since there are no symptoms, and provides some tips for preventing hypertension including eating healthy, maintaining a low fat diet, exercising regularly, and maintaining a healthy weight. Blood pressure is the force of blood on the walls of veins and arteries and is measured in millimeters of mercury (mmHg), represented by two numbers - the systolic pressure when the heart beats and the diastolic pressure between beats.