What is Blood Pressure?

Blood-PressureThe doctor is watching Ms. Lin’s blood pressure. She wants to understand what blood pressure is and why it’s so important. Let’s explain:

The heart is a pump that provides the force needed to move blood around your entire body and return it back to the heart. Blood moves around your body through a series of blood vessels, called arteries, veins and capillaries.

Arteries carry blood away from your heart. Arteries have thick walls so they can handle the high pressure and velocity that expels your blood out of your heart.

Veins carry blood back to your heart from the rest of your body. The pressure of the blood returning to the heart is very low, so the walls of veins are much thinner than arteries.

Capillaries are tiny blood vessels that connect arteries and veins. Their walls are very thin. The blood in capillaries flows slower to allow time for fluid and nutrients to move between the blood and your body’s tissues. Blood pressure measures the force or pressure in your arteries when your heart beats. It is represented as a ratio of two numbers, such as 120 over 80 or 120/80. The top number indicates the pressure in your arteries when your heart contracts, called systolic pressure. The bottom number is the pressure in your arteries between heartbeats, when your heart relaxes and refills with blood, called diastolic pressure.

Maintaining normal blood pressure is important for the health of your blood vessels. High blood pressure or hypertension can damage and weaken your blood vessels. Use the chart below, adapted from the American Heart Association, to determine your blood pressure category.

CategorySystolic

[Top number]

Diastolic

[Bottom number]

Normalless than 120less than 80
Pre-high blood pressure120 to 13990 to 99
High blood pressure140 or higher100 or higher

Follow these Tips to maintain a healthy blood pressure:

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