What is Blood Pressure? Blood pressure can be defined as the pressure exerted by blood on the vessels. The pressure exerted by the heart as it contracts and throws blood into the vessels is systolic, popularly known as systolic blood pressure. As a result of the relaxation of the heart, the pressure that still exists in the vessels is diastolic, popularly known as diastolic blood pressure. High blood pressure, also known as hypertension, refers to high levels of blood pressure in the veins. Hypertension...