Do you feel dizzy, especially when you stand up or have to stand for prolonged periods? Do you have low blood pressure? You might want to learn what POTS or dysautonomia is then.
Many people who suffer from Lyme Disease, Chronic Fatigue, or any of the other mysterious maladies of today, develop dysautomia or POTS.
Dysautonomia– Dysautonomia is the dysregulation of the autonomic nervous system. This is what controls organ function throughout the body. It is involved in the control of heart rate, blood pressure, temperature, respiration, digestion and other vital functions. Dysregulation of the autonomic nervous system can produce the apparent malfunction of the organs it regulates. Read more here
Postural Orthostatic Tachycardia Syndrome-(POTS)– POTS is a disorder characterized by the body’s inability to make the necessary adjustments to counteract gravity when standing up. What happens with POTS is your heart rate increased upon standing and your blood pressure drops. So you aren’t getting the necessary blood to deliver oxygen to your brain. The hallmark symptom of POTS is an increase in heart rate from the supine to upright position of more than 30 beats per minute or to a heart rate greater than 120 beats per minute within 12 minutes of head-up tilt. To read more go to: http://www.dinet.org/index.php/information-resources/pots-place/pots-symptoms
Neurocardiogenic Syncope (NCS) or Vasovagal Syncope– This disorder is characterized by an episodic fall in blood pressure and/or heart rate that results in fainting or near fainting. It can happen for seemingly no reason at all of it can occur in response to a trigger, with a corresponding malfunction in the parts of the nervous system that regulate heart rate and blood pressure. When heart rate slows, blood pressure drops, and the resulting lack of blood to the brain causes fainting. 
Is there tests for POTS?
Yes, first your doctor will take your blood pressure, first laying down, then sitting up, then standing up. If your blood pressure lowers, but your heart rate speeds up, he may refer you for a tilt table test.
For a tilt table test, you will have to lay down on a table with a foot-support, then tilting the table upward. You will be strapped on. The table starts off in a horizontal position and then slowly tilts up to a completely vertical position. The patient’s blood pressure, pulse, and symptoms are monitored throughout the test. They will do this first without medication, then they will add a medicine through a previously asserted iv line. The medicine commonly used is glyceryl trinitrate or isoproterenol, to create further susceptibility to the test. Symptoms, blood pressure, pulse, electrocardiogram, and blood oxygen saturation are recorded throughout the test.