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Blood Pressure Numbers: When to Get Help

Topic Overview

If you check your blood pressure, you may wonder when an abnormal reading means you should call your doctor. This information can help you understand what your blood pressure numbers mean and when you need to call for help.

What do blood pressure numbers mean?

Your blood pressure consists of two numbers: systolic and diastolic. Someone with a systolic pressure of 117 and a diastolic pressure of 78 has a blood pressure of 117/78, or "117 over 78."

Normal blood pressure is less than 120/80 ("120 over 80").

If the first (systolic) number is: OR the second (diastolic) number is: Your blood pressure is:1
120 to 139 80 to 89 Higher than normal (prehypertension)
140 to 159 90 to 99 High
160 or more 100 or more Very high

In general, the lower your blood pressure, the better. A blood pressure reading of less than 90/60 is normal as long as you feel okay.

What can cause a short-term change in blood pressure?

It's normal for blood pressure to go up and down throughout the day. Things like exercise, stress, and sleeping can affect your blood pressure. Some medicines can cause a spike in blood pressure, including certain asthma medicines and cold remedies.

A low blood pressure reading can be caused by many things, including some medicines, a severe allergic reaction, or an infection. Another cause is dehydration, which is when your body loses too much fluid.

When should you get help for an abnormal blood pressure reading?

One high or low blood pressure reading by itself may not mean you need to call for help. If you take your blood pressure and it is out of the normal range, wait a few minutes and take it again. If it's still high or low, use the following guidance.

Call 911 anytime you think you may need emergency care. For example, call if:

  • You passed out (lost consciousness).

Call your doctor now or seek immediate medical care if:

  • Your blood pressure is much higher than normal (such as 180/110 or higher).
  • You think high blood pressure is causing symptoms such as:
    • Severe headache.
    • Blurry vision.
    • Nausea or vomiting.

Call a doctor if:

  • Your blood pressure is 140/90 or higher on two or more occasions.
  • You think you may be having side effects from your blood pressure medicine.
  • Your blood pressure is usually normal and well controlled, but it goes above the normal range on more than one occasion.

References

Citations

  1. Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (2003). Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure JNC Express (NIH Publication No. 03–5233). Bethesda, MD: U.S. Department of Health and Human Services.

Other Works Consulted

  • Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (2003). Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure JNC Express (NIH Publication No. 03–5233). Bethesda, MD: U.S. Department of Health and Human Services.

Credits

By Healthwise Staff
E. Gregory Thompson, MD - Internal Medicine
Robert A. Kloner, MD, PhD - Cardiology
Last Revised April 5, 2013

This information does not replace the advice of a doctor. Healthwise, Incorporated disclaims any warranty or liability for your use of this information. Your use of this information means that you agree to the Terms of Use. How this information was developed to help you make better health decisions.

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