What Is Normal Blood Pressure?
“Normal” is the blood pressure that is found in a large population. But what is normal blood pressure is not the best one for you. Read on and you be the judge.
If you go out and measure the height of a large number of randomly selected adult males your results would be similar to this:
- A very few would be 5 ft 0 in or less.
- A very few would be 6 ft 10 in or more. (NBA not withstanding)
- A very large number would measure in and around the middle, 5 ft 9 in to 5 ft 10 in.
If you plotted these on a simple X and Y graph where X is the height and Y is the number of males for each height you would get a curve like this:
Very low at the left (few very short males) and then rising as you move to the middle of the X axis (many average height) and then falling as you move farther to the right (few very tall). It would look like this:
This is called a Bell Curve because it looks like –you guessed it– a bell. Most things that can be measured will look like this including:
- The brightness of stars, or their size.
- The size of grains of sand on a beach.
- The size of shellfish (I’ve done this one).
- And many, many others including blood pressure.
What Is Normal Blood Pressure ?
If you do this for blood pressure you get a bell curve. The middle or average is probably around 138/80. Thus these middle blood pressures are what we would call normal. But the big question is this: What blood pressure is associated with the least chance of having a stroke, heart attack, kidney failure or heart failure or any of the unpleasant events attributed to high blood pressure? Unfortunately, this “ideal blood pressure” is not the average blood pressure that is found on our bell curve.
That blood pressure associated with NO increase in the incidence of events is found, after much scientific study, to be 115 over 75. This is well to the left of the middle of the bell curve or the average blood pressure found.
As the blood pressures rise above 115/75 one can observe an increased incidence of the above-mentioned complications. This increased incidence worsens as the blood pressure increases.
Doctor’s Practical Guide:
Let’s not talk about what is normal blood pressure anymore. “Normal” is what is found but “Normal” is not what is desirable. Normal is what is found but what is found is not desirable.
From now on let’s use the term desirable. That would mean the blood pressure that is not associated with any increase in adverse events and does not need any lowering. That is 115/75.
Don’t pay much attention to everybody else’s blood pressure. Concentrate on your own. As you read other pages on this website you’ll learn that the only way to really know your own blood pressure is to take it yourself. It’s easy and even fun. See How and Why at How To Take Blood Pressure.
See if your blood pressure is desirable. If it is, you need not think any more about what is normal blood pressure. If it is not desirable, see your doctor.
Here is a table of the classification of various levels of blood pressure:
Blood Pressure Classification
| 120-139 || 80-89
|| Hypertension Stage 1
| 160 or over
|| 100 or over
|| Hypertension Stage 2
This is one aspect of your health where you can take charge. It’s your life.
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