TriStar Medical Group - December 05, 2017

For the first time in 14 years, the American Heart Association changed their blood pressure guidelines. The new guidelines have lowered the number for what’s considered high blood pressure, also called hypertension. The result: Nearly half of American adults are now considered hypertensive.

Find out more about the new guidelines from the American Heart Association and the American College of Cardiology, plus how to check your numbers and lower your hypertension risk.

How to understand your numbers

Blood pressure is depicted as a fraction or a division equation, with a larger number on top and a small number on the bottom, separated by a slash.

The top number is systolic blood pressure, which measures the pressure inside the arteries when the heart contracts or beats. The bottom number, diastolic blood pressure, measures the pressure in the arteries at rest, between heartbeats. So, a blood pressure reading that’s 120/80 means the systolic blood pressure is 120 and diastolic is 80.

“If your blood pressure is high, your heart muscle is pumping against high resistance,” explains Khalil Afsh, MD, an internist and clinical lipidologist with Orange Park Medical Center in Jacksonville, Florida.

Given enough time pumping against high resistance, says Dr. Afsh, the heart will hypertrophy, or grow bigger. This can lead to impaired blood flow, arrhythmia and cardiac arrest.

Under the new guidelines, approximately 103 million adults in the US have high blood pressure. Prior to the new guideline release, about 70 million Americans had hypertension. It’s in your best interest to know your numbers because high blood pressure can lead to a host of problems, such as artery damage, stroke, heart attack and even kidney and eye damage.

What’s changed under the new guidelines

The guidelines for what’s considered normal blood pressure have remained the same: A blood pressure reading of less than 120 mm Hg systolic and less than 80 mm Hg diastolic is considered normal. However, the new guidelines now define hypertension as a reading above 130 mm Hg systolic or 80 mm Hg diastolic. This is a change from the old definition of hypertension—140/90 and higher.

Under new guidelines, 46 percent of American adults will be considered hypertensive, up from 32 percent under old guidelines.

The new guidelines also eliminated the category of prehypertension, once defined as a blood pressure reading between 120 and 139 systolic or 80 to 89 diastolic. Now, the guidelines list:

  • Elevated: Systolic between 120 and 129 and diastolic less than 80
  • Stage 1: Systolic between 130 and 139 or diastolic between 80-89
  • Stage 2: Systolic at least 140 or diastolic at least 90—previously classified as stage 1

If your reading shows systolic blood pressure above 180 or diastolic above 120, this is considered a hypertensive crisis, and patients should seek prompt medical care.

Research suggests complications can arise before blood pressure reaches 140/90. These changes will encourage early intervention to prevent any further increase in blood pressure levels and reduce the likelihood of hypertension-related complications, like stroke, vision loss and heart attack

But pressure that’s too low can cause its own set of problems. Hypotension, or low blood pressure, can lead to blurry vision, confusion, dizziness, fainting, lightheadedness, nausea and vomiting, fatigue and weakness. Sudden and drastic drops in blood pressure can starve vital organs like the heart and brain of oxygen. Hypotension, unlike hypertension, doesn’t have a hard and fast range. As long as your low blood pressure doesn’t cause any symptoms, you don’t need to worry.

Tools of the trade: How to measure your blood pressure

Blood pressure is measured in millimeters of mercury or mm Hg. Why mercury? Take a closer look at the blood pressure cuff the nurse or doctor puts around your arm. The cuff is called a sphygmomanometer and, even today, many contain mercury to measure barometric pressure in the arteries, according to Afsh.

The cuff is inflated to squeeze the artery and prevent blood from flowing, then the air is released. When the blood starts flowing again, the doctor or nurse will look at the pressure reading and determine the systolic blood pressure. “When the pulse goes away, we’re measuring diastolic blood pressure,” says Afsh.

Afsh says he tests blood pressure at least once more after a reading comes back high. “When someone comes to our practice and we find high blood pressure, we ask the patient to relax and then measure again,” he says. “Anxiety can raise blood pressure.”

Talking while your blood pressure is being monitored or having a full bladder can also throw the reading off. Sometimes someone can have high blood pressure in one arm and not the other due to a problem with their veins, adds Afsh. “I usually go with the lower reading because when you have high blood pressure in one arm, there’s probably a blockage.”

You might want to get a device to monitor your blood pressure at home. Many people’s readings are higher in the doctor’s office than they are at home because doctors make them nervous; it’s a phenomenon known as white coat hypertension.

Look for a device that takes measurements from the upper arm and can be used on both arms. It’s a good idea to bring the device to your healthcare provider’s office to make sure it works correctly and you know how to use it properly.

What you can do about high blood pressure

There is no cure for high blood pressure, but a combination of lifestyle modifications and medication can help manage the condition, and reduce your risk of complications. Your doctor is most adept to guide you through the changes you should be making, which might include:

  • Quitting smoking
  • Limiting salt intake
  • Scaling back alcohol consumption
  • Eating a well-balanced diet
  • Upping daily physical activity
  • Maintaining healthy weight
  • Sticking to your medication schedule


Content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.