Home HealthTopics Health Centers Reference Library Research
Join us on Facebook Join us on Facebook Share on Facebook

High Blood Pressure

What is High Blood Pressure?




Blood Pressure Numbers


You most often will see blood pressure numbers written with the systolic number above or before the diastolic number, such as 120/80 mmHg. The mmHg is millimeters of mercury—the units used to measure blood pressure.




Category  Systolic  - top number   Diastolic - bottom number
Normal Less than 120 And Less than 80
Prehypertension  120-139 Or 80-89
High blood pressure Stage 1 140-159 Or 90-99
Stage 2 160 or higher Or 100 or higher






The ranges in the table apply to most adults aged 18 and older who do not have short-term serious illnesses.

Blood pressure does not stay the same all the time. It lowers as you sleep and rises when you wake up. Blood pressure also rises when you are:

If your numbers stay above normal most of the time, you are at risk for health problems.

All levels above 120/80 mmHg raise your risk, and the risk grows as blood pressure numbers rise. "Prehypertension" means you are likely to end up with HBP, unless you take steps to prevent it.

If you are being treated for HBP and have repeat readings in the normal range, your blood pressure is under control. However, you still have the condition. You should see your doctor and follow your treatment plan to keep your blood pressure under control.

Your systolic and diastolic numbers may not be in the same blood pressure category. In this case, the more severe category is the one you are in. For example, if your systolic number is 160 and your diastolic number is 80, you have stage 2 HBP. If your systolic number is 120 and your diastolic number is 95, you have stage 1 HBP.




Blood pressure tends to rise with age. Following a healthy lifestyle helps some people delay or prevent this rise in blood pressure.  If you have HBP, you can take steps to control it and reduce your risk of related health problems. Key steps you can take include:


Source: What is High Blood Pressure? National Heart, Lung and Blood Institute

For more information:


Last Reviewed: Jan 14, 2014