What Is Dysautonomia?

Dysautonomia is a dysfunction of the autonomic nervous system. The autonomic nervous system regulates most of our body’s systems including cardiovascular, gastrointestinal, urinary, bowel, temperature regulation, reproduction and our metabolic and endocrine systems[1]. “Dysfunction of the autonomic nervous system can produce the apparent malfunction of the organs it regulates[2].”

There are several kinds of dysautonomia, including: postural orthostatic tachycardia syndrome, neurocardiogenic syncope, pure autonomic failure, and multiple system atrophy. The first two often overlap with ME/CFS and fibromyalgia.

[1] National Dysautonomia Research Foundation. www.ndrf.org.

[2] Dinet: Dysautonomia Information Network.  potsplace.com

Boyce-Thompson arboretum photo by Allan Hope.

Orthostatic Intolerance

Orthostatic intolerance is traditionally defined as feeling lightheaded upon standing. But it can mean so much more. This term can include neurocardiogenic syncope and postural orthostatic tachycardia syndrome. It can include a drop in blood pressure while standing, or for some the heart rate rapidly increases.  Symptoms can range from mild all the way to completely disabling. The symptoms get worse, the longer the person stands.

Neurocardiogenic Syncope / Neurally Mediated Hypotension

Neurocardiogenic syncope (NCS) is also called neurally mediated hypotension (NMH). Syncope means a loss of consciousness due to “a reduction in blood supply to the brain[i].” Whenever a person stands up, blood starts to pool toward the feet. In a normal person, the brain adjusts by increasing the heart rate and tightening the blood vessels to compensate for the effects of gravity. In NCS, the blood pressure falls too low instead.

The Canadian definition of ME/CFS says that in those with neurally mediated hypotension[ii] the blood pressure drops when the person stands up or stands very long.  Symptoms can include lightheadedness, dizziness, difficulty responding to questions, and sometimes fainting. The patient grows weak and needs to lie down to recover. It can be quite disabling for some.

“Common NMH symptoms, such as lightheadedness, nausea, fainting, fatigue and cognitive dysfunction, typically occur after physical exertion, prolonged periods of standing or exposure to a warm environment (such as a hot shower)[iii].”

NMH can have symptoms such as weakness, sweating, pallor, visual disturbances, abdominal discomfort, headache, and pins-and-needles[iv]. The feet or legs can take on a bluish mottled color.

There is a “miscommunication” between the heart and the brain[v]. Because patients have low blood volume and their blood pools in the veins when they stand, “the amount of blood in the pumping chamber of the heart is reduced[vi].” 

The tilt table test is used to diagnose NMH. The patients lie down on a table which is then tilted to 60 or 70 degrees. Within a few minutes, symptoms occur. “Their average blood pressure dropped from 105/64 to roughly 65/40 [vii].”

Treatment for NMH can include more salt and water in the diet, and medicines such as Florinef and beta blockers. Studies found that “psychiatric illness was not responsible for autonomic test abnormalities[viii].”


[i] National Dysautonomia Research Foundation. www.ndrf.org.

[ii] Bruce M. Carruthers, MD, Anil Kumar Jain, MD, et al. “Myalgic Encephalomyelitis / Chronic Fatigue Syndrome: Clinical Working Case Definition, Diagnostic and Treatment Protocols.” Journal of Chronic Fatigue Syndrome, Volume 11, Number 1. The Haworth Press, Inc. 2003. Page 18.

[iii] Jamie L. Davis. “The Autonomic Nervous System: Neurally Mediated Hypotension in CFS”. The CFIDS Chronicle. Winter 1997. Page 77.

[iv] Dinet: Dysautonomia Information Network. potsplace.com

[v]Roger Burns. “Hopkins Research Links Chronic Fatigue and Blood Pressure”. CFS-NEWS Electronic Newsletter. Washington, D.C. April 20, 1995.

[vi] Jamie L. Davis. “The Autonomic Nervous System: Neurally Mediated Hypotension in CFS”. The CFIDS Chronicle. Winter 1997. Page 77.

[vii] Roger Burns. “Hopkins Research Links Chronic Fatigue and Blood Pressure”. CFS-NEWS Electronic Newsletter. Washington, D.C. April 20, 1995.

[viii] “Autonomic Nervous System Abnormalities Found in CFS, According to Beth Israel Deaconess Researchers”. Beth Israel Deaconess Medical Center. June 3, 1997.

Postural Orthostatic Tachycardia Syndrome

According to the Vanderbilt University Autonomic Dysfunction Center[i], postural orthostatic tachycardia syndrome (POTS) is a form of orthostatic intolerance. In other words, when standing up, the symptoms get worse. The heart rate increases by at least 30 beats per minute upon standing. It was estimated that 500,000 Americans suffered from POTS, many of whom were females under 35 years old.

POTS symptoms can include lightheadedness, palpitations, nausea, trembling, irregular breathing, poor concentration, tiredness, pooling of blood in the legs, and sometimes fainting. Blood volume is often too low. Relief normally comes by lying down to recover. “Patients can be severely impaired by these symptoms and signs[ii].” It can take a large toll on lifestyle and ability to work.

A study at the Mayo Clinic[iii] clearly shows that POTS is a bit more disabling than chronic heart failure and chronic obstructive pulmonary disease.

In my case, when I stand, my heart rate goes up. Then it gradually gets more arrhythmic until the heart monitors can’t read it. Within five minutes, my heart gets strained. My legs swell, because my blood pools in my legs and doesn’t get back up to my heart and brain like it needs to.

The longer I stand, the harder it is to think and speak. I have to sit down frequently. If I have to stand more than a couple of minutes, I move my legs around to try to get the blood back up to my brain. I have to lie down exhausted and unable to function if I stand even 10 minutes. If I stand repeatedly over an hour or so (with frequent sitting down breaks), it can take me hours, if not days, to recover.

Work that requires repeated bending over, such as unloading a dishwasher is quite difficult. My husband has to do most of the physical work, such as shopping and cleaning.


[i] Vanderbilt University Medical Center. http://www.mc.Vanderbilt.Edu/gcrc/adc/index.html. 1999.

[ii] Ibid., Vanderbilt.

[iii] L.M. Benrud-Larson, M.S. Dewar, P. Sandroni, T.A. Rummans, J.A. Haythornthwaite, & P.A. Low. “Quality of life in patients with postural tachycardia syndrome.” June 2002. Mayo Clinic Proceedings. 77, 531-537. http://www.mayoclinicproceedings.org/article/S0025-6196%2811%2961995-2/abstract