Blood Pressure: What Is It & Why Do I Care?

At the start of any doctor visit, you sit down, roll up your sleeve, and the nurse straps a blood pressure cuff onto your arm. There’s a lot of squeezing, and then the machine beeps and spits out a number for the nurse to record in your chart.

So what just happened?

Blood Pressure: The Silent Killer

Health care providers track blood pressure to screen for deadly diseases. Some call high blood pressure the “silent killer” because you can have it for years without any symptoms at all, but over time it causes damage to vital organs like your heart, brain, and kidneys.

What is blood pressure?

Blood pressure measures the pressure in your arteries (blood vessels) when your heart is both beating and resting.

Why are there two numbers? What do they mean?

The top number is larger and is called the “systolic” blood pressure. This is the pressure in your arteries when your heart contracts and pushes blood out to your body.

The bottom number is smaller and is called the “diastolic” blood pressure. This is the pressure in your arteries when your heart is relaxed in between beats.

What do these numbers mean for me?

High blood pressure puts you at risk for what healthcare providers call “cardiovascular events” — such as heart attack and stroke. Individual risk varies with age, gender, and your personal health history. Ask your doctor.

Why does the cuff pump up so tight on my arm?

The cuff temporarily stops blood from flowing through the major artery in your arm (called the brachial artery). Then it slowly releases and detects the point where the pressure from your heart pump overcomes the pressure from the cuff. That point is your “systolic” blood pressure. Some people find the cuff uncomfortable, but it’s not harmful to your health.

Why do I have to sit up straight, rest my arm, and not talk while my blood pressure is being taken?

It’s important for your health care provider to use proper technique to measure your blood pressure. Good posture allows them to accurately place the cuff on your arm and ensure the correct cuff size. It also ensures that the cuff is at the level of your heart to give an accurate reading of the pressure from your heart.

Poor posture, clenching your hand or tensing your arm muscles, dangling your legs and feet, or talking can lead to an inaccurate blood pressure reading.

What YOU can do to ensure an accurate blood pressure reading

  • Don’t smoke or drink caffeine for 1 hour before your appointment
  • Relax and sit quietly

  • Sit up straight with your feet flat on the floor

  • Don’t make a fist

Read more about high blood pressure from the American Heart Association, and talk with your doctor about your blood pressure goals.

Posted by Angie Hoth PharmD MPH on January 7, 2014