Low blood pressure, hypotension, is often confused with hypertension because they sound similar. However they are complete opposites. Both however do have serious health consequences. Blood pressure is controlled by the autonomic nervous system. This system uses a vast network of hormones, receptors and nerves to balance the effects of the sympathetic nervous system (which raises blood pressure) and the parasympathetic nervous system (which lowers blood pressure). This control occurs on a constant basis and is rapid. This allows people to exercise and perform other activities without a drastic change in blood pressure.

There are three main mechanisms, or causes, of low blood pressure.

The most common mechanism is reduced blood volume. This is called hypovolemia and can have many different causes. Hemorrhage, or massive blood loss; not drinking enough fluids such as water or juice; or persistent diarrhea or vomiting can all cause reduced blood volume. Another cause of hypovolemia is excessive diuretics use. This causes the body to produce excessive amounts of urine, which can reduce the amount of fluid in the body very quickly.

Another mechanism that causes low blood pressure is decreased cardiac output. This is usually caused by heart failure of some type. This cause of hypotension can quickly lead to cardiogenic shock, or shock caused by a lack of blood circulation. Arrhythmias, or an irregular heartbeat, can cause cardiogenic shock. A type of medication, beta-blockers, lowers blood pressure by decreasing both the heart rate and the pumping ability of the heart. This results in decreased cardiac output and may even cause hypotension. This is one reason doctors always want to know what medications you take, even the over the counter ones.

The third and final, mechanism of hypotension is an insufficient constriction of the arterioles, also known as excessive vasodilation. There are many reasons this can occur, such as a decrease in the sympathetic nervous system output or an increase in the parasympathetic activity caused by a brain injury, or an abnormality in the autonomic nervous system. Excessive vasodilation can also be caused by certain medical conditions such as sepsis (severe untreated infection) or acidosis (an increase in blood acidity). It can also be caused by some medications, such as nitrate preparations and some anesthetic agents.

The most common form of low blood pressure is called orthostatic hypotension, or postural hypotension. As the second name implies, it occurs when there is a rapid change of body position, usually from a seated position to standing. It is usually temporary. This is the most commonly caused by low blood volume. Taking blood pressure measurements while the person is seated, lying down and standing can confirm this. The second form of hypotension is called neurocardiogenic syncope and commonly results in fainting. A sudden drop in blood pressure while standing characterizes it.

The other form of hypotension is rather rare and is called postprandial hypotension. This form of hypotension occurs about 30 minutes to an hour after eating. It occurs shortly after eating because it is associated with digestion and the intestines need for increased blood flow. It is caused by the body being unable to compensate for this. Some doctors believe this is caused by a faulty or aged autonomic nervous system.

Michael Russell, Your Independent guide to Blood Pressure

If you know the cause of low blood pressure then treat the cause first to treat low blood pressure. Chronic low blood pressure can be treated with life style changes and diet management. You can easily control your blood pressure to normal limits by making following changes to your daily life style.

Use more salt. Doctors often suggest you to decrease salt intake, as sodium can increase blood pressure. But this is an advantage for people with low blood pressure. If you are patient of heart failure then consult your doctor before increasing salt in your diet.

Drink lot of fluids -- You may take 10 glasses of fluid a day. During exercise and hot weather you should take fluids rich in sodium and potassium

Take extra salt and water during illness like flu and cold. During flu you may lose lot of fluid.

Have your doctor evaluate your medicine and omit that drug that is causing too low blood pressure.

To promote blood flow, have regular exercise.

If you are having postural hypotension, then be careful while standing up from lying or sitting position. Breath deeply for few minutes before standing up. Pump your ankles and feet a few times before standing up to increase circulation. For few minutes sit upright on edge of bed before standing up. Cross your thighs and legs in a scissors fashion and squeeze or put one foot on a chair and lean as far forward as possible. These maneuvers increase blood flow from your legs to heart.

Slightly elevate head of your bed while sleeping by placing bricks under the head of bed.

Avoid heavy lifting

Do not strain when you are in toilet

Don't take prolong hot water baths, if you are having symptoms while taking bath, sit down. It is better to keep a chair in shower to help prevent injury.

If your blood pressure gets down after taking meal, then you should take small amount of frequent meals. Better to rest after taking meal. Do not take antihypertensive drugs before meal. Don't take high carbohydrate diet like potatoes, rice, pasta and bread. You may take caffeinated coffee with your meals. caffeine can increase blood pressure, as caffeine is known to cause other problems as well so take advice from your doctor before increasing caffeine in your diet. 2 cups of coffee give you 250 mg of caffeine.

You may wear elastic support stockings to cover your legs and thighs. By doing this, you restrict blood flow to legs, and most of blood retain in upper body parts thus keeping blood pressure normal.

Avoid taking alcohol when you are having low blood pressure as alcohol is also an important dehydrating factor. Drink plenty of water to avoid dehydration.

Increase whole grains, fruits, vegetables, lean chicken and fish in your diet

Medications for Low Blood Pressure

Following medicines can raise blood pressure and physicians often add these drugs to their prescription

Fludrocortisone. It is a mineralocorticoid that can be used for low blood pressure cases like postural hypotension. Its mechanism of action is retention of sodium by the kidney thus retaining more fluid in body and increasing blood pressure. Sodium retention causes loss of potassium at the same time, so when you are taking this medicine it is necessary to take potassium with your diet.

Midodrine. Midodrine activates arterioles and veins receptors to produce an increase in blood pressure. If you have shy drager syndrome then this drug can be useful to treat postural hypotension.

Some other drugs like pyridostigmine, nonsteroidal anti-inflammatory drugs, caffeine and erythropoietin can also increase blood pressure.

Article is written by Dr. Armughan Riaz M.B.B.S Dip Card. To Know more about Low Blood Pressure Symptoms Causes Treatment and cardiovascular diseases High blood pressure symptoms treatment, please visit our site.

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