INFORMATION ON CHRONIC ORTHOSTATIC INTOLERANCE

Walking and running are actually easier than standing or sitting still. In all of these conditions, upright posture makes the person sick.

CAUSES OF CHRONIC ORTHOSTATIC INTOLERANCE

The underlying cause is a disturbance of the autonomic nervous system. This system automatically regulates bodily functions, including heart rate and blood pressure. It also responds to postural or orthostatic stress. Blood is a liquid. It tries to flow downward. When you are standing it tends to run into your legs and feet. This deprives your upper body and, especially, your brain, of an adequate blood supply. The autonomic nervous system prevents this by regulating how the heart beats and by constricting blood vessels in the lower parts of the body, forcing blood upward. In people with Chronic Orthostatic Intolerance, this system doesn't work right and blood tends to pool in the belly, legs, and feet. It will pool in the hands, too, if the arms are dangling. This is what causes the mottling or purpling of the skin usually seen in Chronic Orthostatic Intolerance

When the blood pools in the lower parts of the body, the heart tries to compensate by beating more speedily. But because the blood isn't flowing correctly to the heart and brain, efficiency drops and things get worse. In many cases this leads to a sudden drop in blood pressure, which may cause severe symptoms and even fainting.

The fast heart beat typical of upright posture in Chronic Orthostatic Intolerance is called "tachycardia."

SYMPTOMS OF CHRONIC ORTHOSTATIC INTOLERANCE

The symptoms caused by standing or sitting may include any of the following: fainting, dizziness, nausea, feeling very tired, feeling excessively jittery, having difficulty concentrating or remembering things, experiencing pain in the lower parts of the abdomen or in the legs, mottling or purpling of hands, ankles, feet and legs, hot flushes, sweating, and headache.

TREATMENT OF CHRONIC ORTHOSTATIC INTOLERANCE

Most people with Chronic Orthostatic Intolerance have normal blood pressure when it is taken in a doctor's office. The unexpected drop in pressure typical of NMH can only be detected when it happens--after the person has been standing or sitting silently for a period of time (several minutes to an hour or more). By the time this happens the person is already feeling sick--dizzy, tired, or in pain--from postural stress.