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How Do I Know If I Have Low Blood Pressure?

Your doctor can determine if you are having significant low blood pressure. Symptoms of dizziness and lightheadedness upon standing do not necessarily mean that you have postural hypotension, or low blood pressure. A wide range of underlying conditions may cause these symptoms. It's important to identify the cause of the low blood pressure so the appropriate treatment can be given.

First, your doctor will look at your history, including your age, your specific symptoms and the conditions under which the symptoms occurred. Then he or she may perform repeated evaluation of your blood pressure and pulse rate after you've been lying down for at least five minutes and after you stand quietly for one minute and for three minutes to look for postural hypertension.

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

More sophisticated home ECG monitoring (a Holter monitor or event monitor) may be necessary to check for heart problems that occur intermittently.

An exercise stress test or electrophysiology test (EP test) may also be helpful.

Serious forms of postural hypotension may require a test called a tilt table test. This test evaluates the body's reaction to position and changes in position. The person lies on a table and is strapped to it, then 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?
If you have an underlying medical problem that causes low blood pressure, seek treatment for the underlying condition. For many people, chronic low blood pressure can be effectively treated with diet and lifestyle changes.

Initially, your doctor may counsel you to increase your blood pressure by making these simple changes:

• Eat a diet higher in salt.
• Drink lots of non-alcoholic fluids — a minimum of eight glasses per day. Sports drinks that are high in sodium and potassium are recommended, especially during exercise or in hot weather.
• Consume extra salt and 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 identify any that may be causing your symptoms.
• Get regular exercise to promote blood flow.
• Be careful when rising from a prone or sitting position. To improve circulation, stretch your feet back and forth 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 5-20 degrees by placing bricks or blocks under the head of bed.
• Avoid heavy lifting.
• Avoid straining while on the toilet.
• 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 chair or stool that is specifically designed for showers or bath tubs.
• To avoid problems with low blood pressure after meals, try eating smaller, more frequent meals and resting after eating to lessen episodes of dizziness. Avoid taking low blood pressure drugs 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.
• If tolerated, drink coffee in the morning. The amount of caffeine normally found in two cups of coffee (250 mg) can decrease low blood pressure in young adults and can be safely used by older adults as well. If these measures don't lessen the problem, you may need medication.

• Fludrocortisone. Fludrocortisone is a mineralocorticosteroid that appears to be effective for most types of postural hypotension, or 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. Therefore, when taking fludrocortisone, it's important to also take adequate amounts of potassium each day. Fludrocortisone has none of the anti-inflammatory properties of cortisone or prednisone and it is not a muscle-building agent.
• Midodrine. Midodrine activates receptors on the arterioles (smallest arteries) and veins to produce an increase in blood pressure. Studies show that it is effective in improving standing blood pressure in people with postural hypotension related to nervous system dysfunction, such as those with Shy-Drager syndrome.