What to do if your blood pressure too low

Low blood pressure is a reading of less than 90/60mmHg. It does not always cause symptoms, but you may need treatment if it does.

Symptoms of low blood pressure

Get your blood pressure checked if you keep getting symptoms like:

• lightheadedness or dizziness
• feeling sick
• blurred vision
• generally feeling weak
• confusion
• fainting

This might mean your blood pressure is too low.

If you get symptoms when you stand up or suddenly change position, you may have postural hypotension.

How to check your blood pressure

You can check your blood pressure:

• by asking if a pharmacist can do it
• by asking a practice nurse or GP to do it
• at home yourself using a home blood pressure monitor – Blood Pressure UK has information about choosing a blood pressure monitor

Low blood pressure is a measurement of less than 90/60mmHg.

Treatment for low blood pressure depends on the cause

If a cause can be found, a GP will be able to recommend treatment to ease your symptoms.

For example, they may suggest:

• changing medicines or altering your dose, if this is the cause
• wearing support stockings – this can improve circulation and increase blood pressure

Medicine to increase blood pressure is rarely needed because simple lifestyle measures or treating the underlying cause is usually effective.

How to ease low blood pressure symptoms yourself

Do

• get up slowly from sitting to standing

• take care when getting out of bed – move slowly from lying to sitting to standing

• raise the head of your bed by about 15cm (6 inches) with bricks or heavy books

• eat small, frequent meals – lying down or sitting still for a while after eating may also help

• increase the amount of water you drink

Don’t

• do not sit or stand for long periods

• do not bend down or change posture suddenly

• do not drink caffeinated drinks at night

• do not drink too much alcohol

Causes of low blood pressure

Your blood pressure can vary depending on the time of day. It gradually increases throughout the day.

What you're doing and how you're feeling can also affect it.

There are many possible causes of low blood pressure. It may be low because you're fit and healthy, or you may have inherited it from your parents.

Some people develop low blood pressure as they get older.

It can also be caused by:

• being pregnant
• some medical conditions, such as diabetes
• some medicines

How Do I Know if I Have Low Blood Pressure?

Low blood pressure is not always a sign of a problem. But if you have symptoms of low blood pressure, your doctor can diagnose the condition and uncover the cause. Symptoms of dizziness and lightheadedness when you stand up from sitting or lying down -- with a decrease in your blood pressure -- may indicate a condition called postural hypotension. A wide range of underlying conditions may also cause your symptoms. It's important to identify the cause of low blood pressure so appropriate treatment can be given.

The doctor will look at your medical history, age, specific symptoms, and the conditions under which the symptoms occurred. They will do a physical exam and may repeatedly check your blood pressure and pulse rate -- after you've been lying down for a few minutes, right after you stand up, and within a few minutes after you stand quietly.

Other tests may be performed, such as an ECG (electrocardiogram) to measure heart rate and rhythm and an echocardiogram (an ultrasound test to visualize the heart). You may also have blood tests to look for anemia or problems with your blood sugar levels.

More sophisticated home ECG monitoring (a Holter monitor or "event" monitor) may be necessary to check for heart problems that come and go or an irregular heart beat that can cause your blood pressure to drop suddenly.

An exercise stress test or, less commonly, an electrophysiology test (EP test) may also be helpful.

Some forms of postural hypotension may require a test called a "tilt table" test. This test evaluates the body's reaction to changes in position. The person lies on a table, is safely strapped in, and the table is raised to an upright position for up to an hour. Blood pressure, heart rate, and symptoms are recorded. Often, medications are given to help guide treatment.

What Are the Treatments for Low Blood Pressure?

For many people, chronic low blood pressure can be effectively treated with diet and lifestyle changes.

Depending on the cause of your symptoms, your doctor may tell you to increase your blood pressure by making these simple changes:

• Eat a diet higher in salt.
• Drink lots of nonalcoholic fluids.
• Limit alcoholic beverages.
• Drink more fluids during hot weather and while sick with a viral illness, such as a cold or the flu.
• Have your doctor evaluate your prescription and over-the-counter medications to see if any of them are causing your symptoms.
• Get regular exercise to promote blood flow.
• Be careful when rising from lying down or sitting. To help improve circulation, pump your feet and ankles a few times before standing up. Then proceed slowly. When getting out of bed, sit upright on the edge of the bed for a few minutes before standing.
• Elevate the head of your bed at night by placing bricks or blocks under the head of the bed.
• Avoid heavy lifting.
• Avoid straining while on the toilet.
• Avoid standing still in place for long periods of time.
• Avoid prolonged exposure to hot water, such as hot showers and spas. If you get dizzy, sit down. It may be helpful to keep a chair or stool in the shower in case you need to sit; to help prevent injury, use a nonslip chair or stool designed for use in showers and bath tubs.
• To avoid problems with low blood pressure and lessen episodes of dizziness after meals, try eating smaller, more frequent meals. Cut back on carbohydrates. Rest after eating. Avoid taking drugs to lower blood pressure before meals.
• If needed, use elastic support (compression) stockings that cover the calf and thigh. These may help restrict blood flow to the legs, thus keeping more blood in the upper body.

Medications for Low Blood Pressure

If these measures don't lessen the problem, you may need medication.

The following drugs are sometimes used in treating low blood pressure.

• Fludrocortisone. Fludrocortisone is a medication that seems to help some types of low blood pressure. It works by promoting sodium retention by the kidney, thereby causing fluid retention and some swelling, which is necessary to improve blood pressure. But this sodium retention also causes a loss of potassium. So when taking fludrocortisone, it's important to get enough potassium each day. Fludrocortisone has none of the anti-inflammatory properties of cortisone or prednisone and does not build muscle like anabolic steroids.
• Midodrine. Midodrine activates receptors on the smallest arteries and veins to produce an increase in blood pressure. It is used to help increase standing blood pressure in people with postural hypotension related to nervous system dysfunction.