In a high blood pressure reading, the top number is called the systolic pressure, while the bottom number is the diastolic pressure. A systolic pressure reading represents the arterial pressure measurement as the heart is beating, and the diastolic reading is the pressure between successive heartbeats, as explained by the American Heart Association. Stage 1 hypertension can have a systolic pressure reading in the range of 140 to 159, or a diastolic pressure that is between 90 and 99.
For example, a blood pressure reading of 150/90 means that the systolic pressure is 150 and the diastolic pressure is 90. The systolic and diastolic pressures are given in millimeters of mercury, as related by WebMD. This blood pressure reading is considered stage 1 hypertension following the guidelines given by the American Heart Association.
Stage 2 hypertension is when the systolic pressure is 160 or above, or the diastolic pressure is 100 or over. Stage 3 hypertension is when a person has a systolic reading that is 180 or over, or a diastolic reading of 110 and above. Stage 3 hypertension can require immediate medical attention.
Blood pressure is measured with a cuff and monitor. A normal blood pressure reading is given as a systolic pressure that is 80 or below over a diastolic pressure of 80 or less. It is important for people to understand their blood pressure reading because hypertension can lead to serious medical conditions like kidney failure, stroke and heart problems, as stated by the National Heart, Lung and Blood Institute.