What Do Your Blood Pressure Numbers Really Mean?
Your complete guide to what those two numbers are telling you about your heart
Put a thermometer in your mouth and it’s pretty easy for you to determine whether your temperature is too high. Slap a blood pressure cuff on your arm, however, and it’s not quite as clear if the reading’s a real problem.
That’s because blood pressure numbers aren’t as intuitive. What the heck does 120/70 or 130/80 really mean?
The readings might sound like gibberish, but it actually can benefit you to broaden your understanding of them—and how it affects your heart.
What Is Considered High Blood Pressure?
First, a breakdown of what your reading entails. The top number is your systolic pressure, or the pressure that arises from your heart pumping blood into your bloodstream, says Kevin Campbell, M.D., an assistant professor of cardiology at the University of North Carolina.
The bottom number is your diastolic pressure. That’s the relaxation phase of the pumping process, when your heart’s ventricle is filling and getting ready to take in the next pump.
Both numbers are important to your heart health. A normal blood pressure reading will clock in below 120/80.
To put it another way, your systolic will be below 120 and your diastolic will be below 80.
(Low blood pressure, called hypotension, occurs when your reading measures lower than 90/60. Generally, it’s not a medical problem unless it’s associated with another medical condition, or causes symptoms like as dizziness, fainting, or fatigue.)
If your reading hits between 120-139/80-89, you have what’s considered prehypertension. If it reaches above that benchmark, you have hypertension, or full-fledged high blood pressure.
High blood pressure is divvied up into two categories: 140-159/90-99 is stage one hypertension, and 160/100 or higher is stage two hypertension, a more serious condition.
It generally takes three readings to be formally diagnosed with prehypertension or hypertension. If your first reading comes back high, your doctor might have you come back in for a recheck in a week or two.
Why Is High Blood Pressure So Bad?
High blood pressure means your heart has to pump more forcefully to move your blood throughout your body. Over time, this damages your vessels, which makes them more likely to become clogged when fat in your blood—LDL, or bad cholesterol—rolls on through.
As a result, plaque builds up in your arteries, which triggers inflammation throughout your body that can harm your heart, kidneys, brain, and blood vessels. This inflammation raises your risk of heart attack, stroke, kidney disease, and other serious conditions.
“What’s happening is the rest of the body is feeling the effects of the higher pressure,” says Kevin Dunsky, M.D., director of cardiovascular practice development at Mount Sinai. “The higher it is, the more pounding the body is taking.”
High blood pressure probably won’t cause you to die today, but it’s not setting you up for a very long—or healthy—future.
That’s because the cumulative effects of years of this problem can damage your body, says Dr. Campbell. Some issues, like harm to your vessels, can be reversed, but other problems, like damage to your kidneys may be permanent.
The goal of treatment, then, is to keep it from getting worse—or prevent such damage in the first place.
What Can You Do If Your Blood Pressure Is High?
If you’re in the pre-hypertensive range, lifestyle modifications are likely your first-line treatment.
Minimizing added salt, losing weight if you’re carrying extra pounds, not smoking, and exercising can all help reduce and maintain your blood pressure before real damage occurs.
If your numbers aren’t back to a normal range within three to six months, medication might be necessary, says Dr. Dunsky.
With full-blown hypertension, those lifestyle modifications may be used in conjunction with medication as a first-line of treatment.
Your doctor may prescribe beta blockers, diuretics, calcium blockers, ACE inhibitors, or ARBs. These drugs all have different mechanisms, says Dr. Dunsky, but they mainly help to dilate the arteries and decrease the work of the heart.
If your blood pressure is super-high, though, that’s a medical emergency. Readings higher than 180/110 indicate hypertensive crisis, which can cause any unknown aneurisms or blood vessel abnormalities in the brain to rupture, leading to a hemorrhagic, or bleeding, stroke.
Your doctor will likely send you to the ER, where they can quickly lower your blood pressure by BP medication through an IV, says Dr. Campbell.