What Is High Blood Pressure?

Nurse checking senior woman's blood pressure
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Blood pressure refers to the amount of pressure on the walls of your arteries. Think of a garden hose. When the water is off, there is no pressure on the walls of the hose. When the water is on halfway, there is some pressure on the walls of the hose. When the water is on full the way, there is more pressure on the walls of the hose.

How Blood Pressure Changes

Your body controls the pressure in your arteries using a complex system of regulators including your heart, kidneys, enzymes, hormones and your nervous system.

Blood pressure is always changing based on your activity level, stress level, time of day, and even the position of your body. Lifestyle factors such as alcohol, caffeine, food, tobacco (smoking), and ​stress can all change your blood pressure.

What is High Blood Pressure?

High Blood Pressure (called hypertension by doctors) is a health condition that occurs when the blood pressure is consistently too high. Blood pressure is measured using a blood pressure gauge. The measurement produces two numbers: an upper (systolic) blood pressure and a lower (diastolic) blood pressure.

Blood Pressure Categories

There are several categories of high blood pressure: normal, pre-high blood pressure, stage 1 high blood pressure and stage 2 high blood pressure. If either of the numbers in your blood pressure measurement are higher than normal, you should work on reducing your blood pressure through lifestyle changes and should seek the care of a physician.

Normal Blood Pressure

  • Systolic: 119 or lower
  • Diastolic: 79 or lower

Pre-High Blood Pressure (prehypertension)

  • Systolic: 120 to 139
  • Diastolic: 80 to 89

High Blood Pressure (hypertension)

Stage 1

  • Systolic: 140 to 159
  • Diastolic: 90 to 99

Stage 2

  • Systolic: 160 or higher
  • Diastolic: 100 or higher


National Institutes of Health