Blood pressure is measured by two numbers: the top number is the systolic pressure (when the heart is pumping blood) and the bottom number is the diastolic pressure (when the heart is at rest).
A normal blood pressure number is below 120/80. Prehypertension is diagnosed between 120/80 – 139/89, Stage 1 hypertension is between 140/90 – 159/99, and Stage 2 hypertension is blood pressure above 160/100. Low BP measures between 90/60. Low blood pressure can be a matter of concern especially to the elderly where it may cause inadequate blood flow to the heart, brain, and other vital organs.