What Is Abnormal Blood Pressure?

Know the ranges for high and low blood pressure

Abnormal blood pressure puts you at risk of several serious health problems including heart attack and stroke. Your blood pressure is a measurement of the force of your blood as it moves through the arteries in your body. It's made up of two numbers—systolic blood pressure and diastolic blood pressure.

Systolic Blood Pressure
  • The first (top) number in a blood pressure reading

  • The force exerted against your artery walls when your heart beats

Diastolic Blood Pressure
  • The second (bottom) number in a blood pressure reading

  • The force exerted against your artery walls when your heart is between beats

High blood pressure is generally of greater concern when talking about risks. It's also called hypertension. Low blood pressure is called hypotension.

What Is Normal Blood Pressure?

A normal blood pressure is a systolic blood pressure that is less than 120 mmHg ) and a diastolic blood pressure that is less than 80 mmHg.

The ACC and AHA recommend that adults should have their blood pressure checked at least once a year. If an adult has one or more risk factors for high blood pressure—for example, a family history or a history of smoking—they should be screened at least twice a year.

What Is High Blood Pressure?

The American College of Cardiology and the American Heart Association (AHA) recognize a couple of stages of hypertension.

Elevated

An elevated high blood pressure means that your systolic blood pressure ranges on average from 120 to 129 millimeters of mercury (mmHg) and your diastolic blood pressure is less than 80 mmHg.

If left untreated, elevated blood pressure puts you at risk for developing stage 1 or stage 2 hypertension.

Stage 1

Stage 1 hypertension means that your systolic blood pressure is between 130 to 139 mmHg or your diastolic blood pressure is between 80 to 90 mmHg.

Stage 2

Stage 2 hypertension means that your systolic blood pressure is higher than 140 mmHg or your diastolic blood pressure is higher than 90 mmHg.

Hypertensive Crisis

If your blood pressure is above 180/120, it's considered a hypertensive crisis and you should seek medical help immediately. Call 911 if you also experience chest pain, back pain, shortness of breath, numbness or weakness, vision changes, or difficulty speaking.

hypertension diagnosis
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Understanding the ACC/AHA Definition

It's important to mention that the definition of high blood pressure according to the ACC/AHA defers slightly from other professional societies, such as the European Society of Cardiology and the European Society of Hypertension (ESC/ESH).

The ESC/ESH defines high blood pressure as a systolic blood pressure that is 140 mmHg or higher or a diastolic blood pressure that is greater than 90 mmHg.

The differences in definition are based on results from large studies that examined the link between blood pressure and the occurrence of heart attacks and strokes.

Symptoms and Complications

Hypertension is often referred to as the "silent killer" because it causes no symptoms (regardless of the stage) unless dangerous complications arise, such as:

  • Heart attack or failure, which may cause chest pain or trouble breathing
  • Stroke, which may cause headache or blurry vision
  • Kidney injury, which may feature an elevated blood creatinine level
BLOOD PRESSURE  SYSTOLIC AND/OR DIASTOLIC
Normal 90-120 and 60-80
Elevated 120-129 and 60-80
Stage 1 Hypertension 130-139 or 80-89
Stage 2 Hypertension Above 140 or Above 90
Hypertensive Crisis Above 180 and/or Above 120
Hypotension Under 90 and Under 60

Treating High Blood Pressure

The treatment of high blood pressure typically involves a combination of lifestyle changes and one or more medications. If you have elevated high blood pressure, lifestyle changes are emphasized in order to avoid the progression to stage 1 or stage 2 hypertension.

Lifestyle Changes

Lifestyle changes that can reduce blood pressure are:

  • Restricting salt in your diet by avoiding processed foods and eating fresh-foods
  • Losing weight, if you're overweight or obese
  • Engaging in regular physical activity—at least 30 minutes a day, most days of the week
  • Limiting alcohol consumption
  • Quitting smoking

Your doctor may also recommend the DASH (Dietary Approaches to Stop Hypertension) diet, which has been found to lower blood pressure. This diet is rich in fruits, vegetables, and whole grains and low in red meats and sweets.

Medications

Medication along with lifestyle changes is often very effective in lowering a person's blood pressure.

The medications for high blood pressure are generally broken into four main categories:

Finding the right medication or combination of medications for your high blood pressure often requires a trial-and-error process. Try to remain patient and keep in close contact with your doctor as your regimen is fine-tuned.

What Is Low Blood Pressure?

Low blood pressure, called hypotension, is defined as a systolic blood pressure that is less than 90mmHg. It has several potential causes, such as:

Low blood pressure is generally not worrisome unless you have symptoms from it, such as lightheadedness, dizziness, or fainting.

Other potential symptoms of low blood pressure (some of which are directly related to the underlying cause) may include:

  • Nausea
  • Blurry vision
  • Cool, clammy skin
  • Fatigue
  • Breathing fast
  • Thirst

Treating Low Blood Pressure 

The treatments for low blood pressure involve addressing the underlying cause.

For instance, if you're experiencing low blood pressure from dehydration, the treatment would be fluid and electrolyte replacement.

A Word From Verywell

Even if your blood pressure is normal, it's important to engage in healthy lifestyle habits—the same ones you would engage in if your blood pressure were high. Again, some key habits include losing weight (if you are overweight or obese), exercising every day, reducing alcohol consumption, and not smoking.

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  1. Whelton PK, Carey RM, Aronow WS, et al. 2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA Guideline for the prevention, detection, evaluation, and management of high blood pressure in adults: A report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice GuidelinesJ Am Coll Cardiol. 2018;71:e127-e248. doi:10.1161/HYP.0000000000000066

  2. Williams B et al. 2018 ESC/ESH Guidelines for the management of arterial hypertension. Eur Heart J. 2018 Sep 1;39(33):3021-104. doi:10.1093/eurheartj/ehy339

  3. American Heart Association. Low blood pressure - When blood pressure is too low. Updated October 31, 2016.

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