Low Blood Pressure

Low blood pressure, generally referred to by medical professionals as hypotension when it is abnormally low, is a physiologic state of ill-health rather than a disease. In fact, the occurrence of low blood pressure is often an indication of another disease. For instance, low blood pressure is a factor that can occur after poisoning with a depressive drug, such as [Page 1031]a barbiturate, and can occur with shock or the onset of poliomyelitis. The low blood pressure can happen either because of a reduction in blood volume or an increase in blood vessel capacity. The opposite is hypertension, high blood pressure.

The blood pressure of all humans is regulated by the automatic nervous system, which utilizes a large network of nerves, receptors, and hormones to balance the effects of the sympathetic nervous system, which is often involved in the raising of blood pressure, and the parasympathetic nervous system, which lowers it. These two counteracting forces allow individuals to maintain an acceptable blood pressure over a wide range of physical and mental activities, and even when they have contracted diseases or are suffering from particular disorders.

Low blood pressure is often accompanied by other medical problems that are usually the way in which people discover their low blood pressure. It may involve an irregular heartbeat, some chest pain, a headache, some shortness of breath, or a fever higher than 101 degrees Fahrenheit (38.3 degrees Celsius). Other problems may involve a severe upper back pain, a stiff neck, dizziness or light-headedness, profound fatigue, or even a loss of consciousness. Obvious signs may involve a burning sensation when urinating, foul-smelling urine, prolonged diarrhea or vomiting, coughing with phlegm, or even a loss of appetite and an inability to eat or drink. It may lead to allergic reactions and have an adverse effect on the taking of medications. Indeed, some food and medication that have been found to cause low blood pressure have been taken by athletes to help them in particular sports. As a result, many of these medications are now banned in world competitions.

One of the main reasons for people suffering from low blood pressure is hypovolemia, or having a reduced blood volume. This can occur when there is a decreased sympathetic nervous system output, or increased parasympathetic activity. It often occurs as a result of serious injury where a person loses much blood, or from an injury to the brain or spinal cord, or can come from an intrinsic abnormality in the automatic system functioning. There can also be other factors in vasodilation, which can come from inappropriate medication, or people undergoing various anesthetic procedures especially spinal anesthesia.

The occurrence of low blood pressure is often an indication of another disease.

There are three main syndromes connected with low blood pressure: orthostatic hypotension, neurocardiogenic syncope, and postprandial hypotension. Orthostatic hypotension comes from low blood pressure when someone stands up, especially standing up quickly. It seems to come from a failure in the automatic nervous system to cope with this change, and often, at its mildest, results in dizziness until the automatic nervous system alters itself to deal with the new situation. The low blood pressure occurs because when a person stands up, there is a reflex constriction in the small veins and arteries to offset the gravitational effects. Although dizziness is common, it may also lead to fainting.

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