Low Blood Pressure

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KEY POINTS

• Low blood pressure usually means blood pressure that is lower than 90/60 or is low enough to cause symptoms.
• Treatment of low blood pressure depends on the cause. You may be given fluids, your medicine or dosage may be changed, or you may be treated for a severe infection or heart problem.
• Follow the full course of treatment prescribed by your healthcare provider. Ask when you can return to your normal activities and how to take care of yourself at home.

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What is low blood pressure?

Low blood pressure usually means blood pressure that is lower than 90/60 or is low enough to cause symptoms.

Blood pressure is the force of the blood on the artery walls as the heart pumps blood through the body. The arteries are the blood vessels that carry blood from the heart to the rest of the body. Normal blood pressure measurements when you have been resting range between 90/60 (“90 over 60”) and 120/80. The first number (90 in the 90/60 measurement) is the pressure when the heart beats and pushes blood out to the rest of the body. The second number (60 in this example) is the pressure when the heart rests between beats.

When blood pressure gets too low, your body may not get enough oxygen-rich blood. This may cause problems with breathing, activity, and thinking. If your blood pressure is very low for too long, your organs may be damaged.

Low blood pressure is far less common than high blood pressure. Another term for low blood pressure is hypotension.

What is the cause?

Low blood pressure may be caused by:

• Some medicines, such as medicines taken to treat high blood pressure, heart problems, or anxiety
• Pregnancy
• Hormone problems, like low thyroid hormone
• Heart problems
• Not enough fluid in the body (dehydration)
• Getting overheated, like when you have been outside in high temperatures

Sometimes a type of low blood pressure called postural or orthostatic hypotension can happen when you stand up after sitting or lying down. It can happen if your body is not able to increase blood flow and narrow blood vessels fast enough when you change your position. Symptoms usually last just a few minutes after you stand up. Older adults are especially at risk for this problem. Examples of causes include lack of fluids, a lack of food, or being overly tired.

Diseases that affect your nervous system such as diabetes can keep your blood vessels from reacting when you stand up, so your blood pressure stays low.

Life-threatening, fast drops in blood pressure can be caused by:

• A loss of blood
• Heart attack
• A severe blood infection
• Severe loss of body fluids (dehydration) from fever, vomiting, or diarrhea
• A reaction to medicine or a severe allergic reaction
• A very high or very low body temperature

What are the symptoms?

Symptoms may include:

• Feeling lightheaded, dizzy, or faint, especially if you suddenly stand up
• Feeling cold, or sweaty
• Feeling very tired
• Fainting
• Nausea

How is it diagnosed?

Your healthcare provider will ask about your symptoms and medical history and examine you. Your provider may take your blood pressure after you lie down for 10 minutes and then again when you sit up and after you stand up. It may be taken again after you walk around for 5 minutes.

Tests to look for possible causes of low blood pressure may include:

• Urine and blood tests
• A chest X-ray
• An ECG (also called an EKG or electrocardiogram), which measures and records your heartbeat

How is it treated?

Treatment of low blood pressure depends on the cause. For example:

• If you are dehydrated, you may be given fluids.
• If medicine is causing your low blood pressure, the medicine or dosage may be changed.
• If you have a severe infection, treating the infection can return blood pressure to normal.

If you have symptoms caused by low blood pressure whenever you stand up, your provider may prescribe medicine to help. Your provider may suggest that you wear tight stockings over your feet and lower legs. These compression stockings help push blood back to your heart. You may also need to learn how to change positions slowly to avoid getting lightheaded.

You may be asked to use a device at home to measure your pressure at different times during the day and night.

How can I take care of myself?

Follow the full course of treatment prescribed by your healthcare provider.

If you have low blood pressure that is causing symptoms, try these tips:

• Don’t skip meals. Eat a healthy diet.
• Avoid being out in the heat for a long time or being too active.
• Drink plenty of liquids every day, unless your healthcare provider has told you to limit liquids, especially in hot weather or when you are working outside.
• If you smoke, try to quit. Talk to your healthcare provider about ways to help you quit smoking.
• If you want to drink alcohol, ask your healthcare provider how much is safe for you to drink.
• If you have been lying down, sit for a moment before standing up, and then stand up slowly. Stand a moment before walking. Walk in place briefly while pulling in your stomach muscles several times. (This helps the return of blood flow from the legs.)

Tell your healthcare provider if you have any symptoms after you start taking a new medicine. Keep all appointments for provider visits or tests.

Ask your provider:

• How and when you will get your test results
• How long it will take to recover
• If there are activities you should avoid and when you can return to your normal activities
• How to take care of yourself at home
• What symptoms or problems you should watch for and what to do if you have them

Make sure you know when you should come back for a checkup. Keep all appointments for provider visits or tests.