Your blood pressure isn't just a number on your chart at the doctor's office — it's also one of the most important indicators of how healthy you are and how healthy you are likely to be in the future.
But what is blood pressure, exactly? In the simplest terms, it's the measure of how hard your blood is pressing on the walls of your arteries as your heart pushes it through your body, according to the American College of Cardiology (ACC).
"Blood pressure is the driving force for delivering blood to all of our organs," Karol Watson, MD, PhD, spokesperson for the American College of Cardiology (ACC) and co-director of the UCLA Program in Preventive Cardiology, tells LIVESTRONG.com.
Dr. Watson likens it to the pressure of a garden hose: You don't want it to be a trickle, but you also don't want it on full-blown, fire-hose level. "You need a nice, steady stream of blood," she says.
Here's what else you need to know about this key measure of your health.
Why Is Blood Pressure Important?
That steady stream of blood delivers oxygen and other nutrients that all the different parts of your body need to survive.
"Blood pressure is critical," says Michael Blaha, MD, MPH, professor of medicine and director of clinical research at Johns Hopkins University's Ciccarone Center for the Prevention of Cardiovascular Disease, adding that blood pressure needs to be high enough to sustain your everyday functions. "There is a blood pressure below which you can't live."
Read more: How Does Cinnamon Reduce Blood Pressure?
Systolic vs. Diastolic Blood Pressure
Your blood pressure measurement is given as two numbers — a larger number "over" a smaller number, like "120 over 80" or "120/80."
The first, higher number is called your systolic blood pressure, which measures the pressure when your heart is actually beating or pumping, Dr. Blaha says.
The second, lower number is your diastolic pressure. This records the pressure when your heart is resting between pumps.
"Systolic blood pressure is probably more important because it's more often uncontrolled," Dr. Watson says. Uncontrolled or high systolic blood pressure is a red flag that you're at risk for heart disease, among other things, according to the American Heart Association (AHA).
What Is a Healthy Blood Pressure Range?
According to 2017 American College of Cardiology and American Heart Association guidelines, a healthy blood pressure is less than 120/80 mm Hg (that's millimeters of mercury, in case you were wondering). Anything above that is considered high and may require treatment.
Any reading below 90/60 is considered low blood pressure, per the Mayo Clinic, but this is generally only a concern if it's accompanied by symptoms, such as:
- Cold, clammy, pale skin
- Rapid breathing
- Blurred vision
- Confusion, especially in older adults
Blood Pressure Chart
Blood Pressure Category
Blood Pressure Range
Less than 120/80
Systolic between 120-129 and diastolic less than 80
Stage 1 Hypertension (High Blood Pressure)
Systolic between 130-139 or diastolic between 80-89
Stage 2 Hypertension (High Blood Pressure)
Systolic at least 140 or diastolic at least 90
Hypertensive Crisis (may require hospitalization)
Systolic over 180 and/or diastolic over 120
Read more: What Is Normal for Blood Pressure?
Factors That Affect Blood Pressure
Many different factors can influence your blood pressure levels, per the Mayo Clinic, including:
- Age (older individuals are more likely to have high blood pressure)
- Family history
- Physical activity
- Body mass index
- Diet (especially how much salt you eat)
- Kidney disease
- Race (African-Americans have a higher risk of developing hypertension)
- Potassium in your diet
- Sleep apnea
- Certain medications, such as decongestants
- American College of Cardiology: “High Blood Pressure.”
- American Heart Association: “Understanding Blood Pressure Readings.”
- American College of Cardiology: “New ACC/AHA High Blood Pressure Guidelines Lower Definition of Hypertension.”
- Mayo Clinic: “High blood pressure (hypertension).”
- Mayo Clinic: "Low blood pressure (hypotension)"