Generally speaking, doctors sometimes refer to a blood pressure of 90/60 as a rough rule of thumb when evaluating patients because experience seems to show that this is the point at which symptoms tend to develop.
In general, if you have no history of medical problems and are not experiencing any symptoms, a low blood pressure reading is not cause for concern. If you discover on your own that your blood pressure is below 120/80, you should mention it to your doctor during your next visit but probably don’t need to schedule a special appointment unless you know that the low reading represents a significant change from your average blood pressure.
Is Low Blood Pressure Dangerous?
With very few exceptions, chronic blood pressure below 120/80 is not dangerous. Low blood pressure is usually considered dangerous only when it causes symptoms or results from sudden blood pressure decreases. In cases where the blood pressure drops suddenly, it isn’t actually the low blood pressure itself that causes the danger, but rather the sudden change from a higher value to a lower value. Sudden changes in blood pressure can cause interruptions in the blood supply to the heart, kidneys and brain, and will almost always be accompanied by distinctive symptoms. An example of this situation is orthostatic hypotension, where changes in body position (usually a change from sitting to standing) are accompanied by a rapid drop in blood pressure. Usually, sudden episodes of low blood pressure are a sign that something else might be wrong, and are typically an indication for a full medical workup.
There is some recent research that suggests chronic low blood pressure may be of unique importance in people who have underlying kidney disease. For these people, chronic low blood pressure appears to trigger a complicated cascade of events that can lead to blood vessel damage and may lead to a stroke. Because this data is relatively new, no clear blood pressure guidelines for these patients have yet been developed.
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