The Relationship Between Hypotension and Chronic Fatigue Syndrome

Chronic fatigue syndrome (CFS) is a crippling disorder characterized by extreme fatigue that cannot be cured by sleep. It is a very mysterious disease, being very difficult to diagnose and treat as it has no known causes. In addition to fatigue, CFS patients experience a variety of other odd symptoms, including hypotension (or low blood pressure).

Blood Pressure Basics

Blood pressure is controlled by a division of the nervous system called the autonomic nervous system. The word "auto' in autonomic is suggestive of its function, which occurs automatically and without conscious thought. In addition to blood pressure, the autonomic nervous system also regulates respiration, digestion, and the actions of the heart.

A collection of reflexes are responsible for mediating blood pressure. These reflexes occur upon the stimulation of pressure sensors embedded in the heart and blood vessels. An example of such a reflex occurs when you stand up; blood in your chest and abdomen pool in your lower extremities in response to gravity. Your heart receives less blood momentarily and interprets this change as low blood pressure. It then proceeds to pump slightly harder to make up for it.

Neurally Mediated Hypotension

When the pressure sensors in the heart detect excessive squeezing, the heart is then instructed to relax slightly, lowering blood pressure to a desired level again. Some people have a condition called neurally mediated hypotension (NMH), where these sensors incorrectly identify the heart squeezing too hard. The sensors trigger the heart to relax slightly, causing dangerous hypotension that can result in nausea, light-headedness, and fainting.

The Tilt Table Test

A person's susceptibility to neurally mediated hypotension is determined through the Tilt Table Test. In the test, a patient lies down on a table which is then tilted, head-up, at a 70 degree angle. The patient is monitored for 45 minutes through blood pressure and verbal response time (a measure of cognitive function). Those with NMH susceptibility will feel lightheaded, dizzy, or have a slower verbal response time.

The CFS Connection

So what does any of this have to do with CFS? Well get this: one study showed that 96% of adults diagnosed with CFS also experienced NMH during a tilt table test in comparison to only 29% of healthy controls. Interestingly, the tilt table test also worsened classic symptoms in CSF patients.

Yet, it gets better: when these same patients were treated with medications used to treat NMH, nine of nineteen patients were cured while seven of nineteen improved significantly. That equates to 84% of patients being greatly improved or cured. The recent studies revealing connections between CFS and NMH are exciting, to say the least. They provide hope that the mysteries of CFS can and will be cracked in the near future.


Photo Credit: compscigrad

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