If blood pressure falls too low, it can cause people to feel dizzy or light-headed and, in extreme cases, can compromise blood flow to the organs. Low blood pressure - or hypotension - is a sign of good health, but can be abnormal in certain situations, such as during severe infection. People with high blood pressure - or hypertension - are at risk of developing heart problems and damage to the walls of the blood vessels. Healthcare professionals measure blood pressure in millimeters of mercury (mm Hg).ĭoctors can use blood pressure as an indicator of a person’s heart health. Blood pressure refers to the force that blood puts on the walls of the blood vessels as the heart pumps blood.