Low Blood Pressure

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.

Blood pressure is measured in millimeters of mercury (mm Hg). The first number in the measurement (90 in the example of 90/60) is the pressure when the heart pushes blood out to the rest of the body. It is called the systolic pressure. The second number (60 in this example) is the pressure when the heart rests between beats (diastolic pressure).

When blood pressure gets too low, your body may not get enough oxygen-rich blood. This may temporarily weaken breathing, body movements, and brain function. Damage may occur if the blood pressure is very low and lasts too long.

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

What is the cause?

Some people, especially older adults, have a type of low blood pressure called postural or orthostatic hypotension. This is low blood pressure that can happen when you stand up after sitting or lying down. It happens when your body is not able to adjust blood pressure and blood flow fast enough for the change in position. Orthostatic hypotension usually lasts for just a few seconds or minutes after you stand up.

Blood pressure that stays low can result from:

• medicine taken to treat high blood pressure, heart problems, or anxiety
• pregnancy
• hormone problems, like low thyroid hormone
• not enough fluid in the body (dehydration)
• lack of food
• standing too long in the heat
• shock from a loss of blood, a heart attack, or other conditions

Life-threatening, fast drops in blood pressure can occur from a loss of blood, severe infections, or a very low body temperature from cold exposure.

What are the symptoms?

Symptoms of low blood pressure may include:

• dizziness, especially if you suddenly stand up
• feeling very tired
• fainting

How is it diagnosed?

Your blood pressure is usually checked when you visit your healthcare provider. If your blood pressure is low and causing symptoms, your healthcare provider will ask about symptoms, what you eat and drink, and if low blood pressure runs in your family. Your provider may take your blood pressure after lying down for 10 minutes, then again after standing up, and again after standing and walking around for 5 minutes.

You may be asked to use a portable blood-pressure measuring device at home, which will take your pressure at different times during day and night.

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

• urine and blood tests
• a chest X-ray
• an electrocardiogram (ECG)

How is it treated?

If your healthcare provider finds something that is causing low blood pressure, treatment of the cause should bring your blood pressure back to normal. For example:

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

Depending on your overall health, your blood pressure goal is usually at least 100/70. Normal blood pressure is usually between 110/70 and 120/80.

If you have low blood pressure whenever you stand up and it bothers you, your provider can try several different medicines to help. You also can 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 dizzy.

How can I take care of myself?

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

• Don’t go too long without eating.
• Avoid being out in the sun for a long time.
• Drink plenty of liquid every day, especially in hot weather or when you are working outside.
• 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. Regular exams by your provider may detect low blood pressure before it becomes a health problem.