Blood pressure is the pressure exerted by circulating blood upon the walls of blood vessel. It is one of the critically important signs of life (vital sign) and is expressed as systolic/diastolic blood pressure. ‘Diastolic’ refers to blood pressure when the heart is at rest between beats. The pressure in the arteries as the muscle of the heart relaxes following its contraction is called diastolic blood pressure. Normal blood pressure is less than 130 mmHg/80 mmHg.
Normal diastolic blood pressure ranges between 60 and 80 mm Hg. A diastolic blood pressure between 80 and 89 indicates prehypertension and a pressure of 90 or higher is considered high. In isolated diastolic hypertension, only the diastolic blood pressure is above normal. Blood pressure doesn’t stay the same all the time. It lowers during sleep and rises when awake. Blood pressure also rises when nervous, excited or active.
Increased diastolic blood pressure is thought to increase severity of aortic and mitral regurgitation, whereas a decreased diastolic blood pressure decreases the severity.