Blood pressure is a measure of how hard your blood pushes against the walls of your arteries as it moves through your body.
It’s normal for blood pressure to go up and down throughout the day, but if it stays up, you have high blood pressure, or hypertension.
When blood pressure is high, it starts to damage your blood vessels, heart and kidneys. This can lead to heart attack, stroke and other problems. High blood pressure is known as a silent killer, because it doesn't usually cause symptoms while it’s causing this damage.
Your blood pressure consists of two numbers: systolic and diastolic. Someone with a systolic pressure of 120 and a diastolic pressure of 80 has a blood pressure of 120/80, usually pronounced as 120 over 80.
The systolic number shows how hard the blood pushes when your heart is pumping. The diastolic number shows how hard the blood pushes between heartbeats, when your heart is relaxed and filling with blood.
High blood pressure is 140/90 or higher, but adults should have a blood pressure of less than 120/80.
Many people fall into the category in between, called prehypertension. If you have prehypertension, you need to make lifestyle changes to bring your blood pressure down. This will help prevent or delay the development of high blood pressure.