What do blood pressure numbers mean?


What does a large split in blood pressure numbers mean? For example, a 26 year old male with a reading of 143/73.



Dear Pumping,

With all the health recommendations out there, it's tough to keep the numbers straight. The cutoff point or "magic number" to remember for normal blood pressure is 120/80. A "large split" between the numbers isn't actually all that informative — it's really more about knowing whether those numbers fall into a healthy range. Read on for specifics about what the numbers mean and how they can help you make health-related decisions.

The first number of a blood pressure reading is the systolic pressure, which is measured when the heart is pumping. The second or bottom number is the diastolic blood pressure, which is measured when the heart is relaxed between beats. The unit, mmHg, simply stands for millimeters of mercury, which is a measurement of pressure, in this case, within your blood vessels. According to the National Heart Lung and Blood Institute (NHLB), healthy adults should have a blood pressure measurement that's less than 120/80. If your systolic measurement is over 120 mm Hg or your diastolic measurement is over 80 mm Hg, then you have an increased risk of high blood pressure, also known as HBP or hypertension. The four different blood pressure categories classified by the NHLB are:

  • Normal: A systolic measurement of less than 120 and a diastolic measurement of less than 80
  • Prehypertension: A systolic measurement of 120 to 139 or a diastolic measurement of 80 to 89
  • Stage 1 HBP: A systolic measurement of 140 to 159 or a diastolic measurement of 90 to 99
  • Stage 2 HBP: A systolic measurement of 160 or higher or a diastolic measurement of 100 or higher

Based on these categories, your example of a measurement of 143/73 falls into the Stage 1 HBP category. However, that doesn't mean you've been diagnosed with HBP. Blood pressure readings vary depending on factors such as stress, excitement, anxiety, and setting. Therefore, it's recommend that you calculate your blood pressure from an average of three readings on separate days. Since you only gave one example for a 26 year-old man, it's impossible to determine if you have HBP or if you just got an inaccurate reading or if there are other factors at play.

For a more precise picture of your health, getting a few more readings may be in order. You may also benefit from having a chat with your health care provider about what might be influencing your blood pressure numbers and whether or not you're dealing with hypertension. Approximately 95 percent of hypertension cases have unknown causes, but most tend to involve factors such as diet, obesity, alcohol abuse, physical and emotional stress, environment, and psychological and genetic factors. The good news is that under the direction of a health care provider, most of these can be mediated by making some lifestyle changes. Suffice it to say, knowing about these numbers can certainly inform decisions you make about your health in the future.

Here's to keeping your heart healthy, whether you're pumping iron or pumping up a blood pressure cuff.

Last updated Oct 02, 2015
Originally published Oct 05, 1995

Can’t find information on the site about your health concern or issue?