Understanding Blood Pressure Numbers: What’s Healthy, What’s Not

“It’s so, so, so important to know your [blood pressure] numbers,” says Michelle Weisfelner Bloom, MD, a cardiologist at Stony Brook University Medical Center.

First reason: High blood pressure is one of the major risk factors for cardiovascular disease. Second: High blood pressure is often called the “silent killer,” because the majority of the time patients with high blood pressure don’t feel any symptoms, says Rachel Bond, MD, a cardiologist at Lenox Hill Hospital.

In many cases, by the time high blood pressure is detected, a lot of the damage—which can sometimes be life-threatening—has already been done. “The only way for you to truly know if you have elevated blood pressure is to go to your doctor and get a wellness visit,” says Dr. Bond.

If you’ve been diagnosed with high blood pressure, your doctor may recommend that you get your blood pressure levels checked regularly, whether that’s checking your blood pressure numbers at home yourself, or seeing your doctor more frequently.  

If you’re over 40 years old or are high risk for blood pressure, it’s recommended that you get your blood pressure checked once a year. If you’re between 18 and 40, get your blood pressure checked every three to five years, or per your doctor’s advice.

What Blood Pressure Numbers Mean

“When we’re thinking about blood pressure, we’re talking about two different numbers: the systolic, which is the top number, and the diastolic, which is the bottom number,” says Paul Knoepflmacher, MD, a clinical instructor in medicine at The Mount Sinai Hospital.

• Systolic blood pressure measures the pressure in your blood vessels when your heart beats.
• Diastolic blood pressure measures the pressure in your blood vessels when your heart rests in between beats.

So if your measurement reads 120 systolic and 80 diastolic, your doctor would say “120 over 80,” or you’d see it written as “120/80 mmHg.”

Your blood pressure reading will fall into one of four categories, according to Dr. Knoepflmacher.

• Normal blood pressure is less than 120 (systolic) over less than 80 (diastolic).
• Elevated blood pressure is between 120 and 129 (systolic) over less than 80 (diastolic).
• Hypertension stage 1 is between 130 and 139 (systolic) over 80 to 89 (diastolic).
• Hypertension stage 2 is 140 or greater (systolic) over 90 or greater (diastolic).

How to Treat High Blood Pressure

In early stages of treatment for high blood pressure, medication may not be necessary. “If the blood pressure is either borderline or it’s on the low end of hypertension, usually we can get away with lifestyle modifications,” says Michelle Weisfelner Bloom, MD, a cardiologist at Stony Brook University Medical Center. “If we need to use a medication, can generally get away with taking one medication.”

Ways to lower blood pressure naturally include maintaining a heart-healthy diet (your doctor may recommend the DASH diet, which is specifically geared to lower high blood pressure), getting enough physical activity, losing weight if you need to, and keeping your stress levels low.

“Once we start to get to the higher [blood pressure] numbers, it’s harder to expect that just changing their lifestyle or taking one medication is going to lower the blood pressure,” says Dr. Bloom. “Those are the situations where we start to have to use more than one medication, sometimes two or three or even  four medications, to get the blood pressure under control.”

Now that you’ve brushed up on your blood pressure smarts, test your knowledge with this blood pressure quiz.