Glad you brought this up, I am now curious about it... Since I am new to this site and just discovered that I have NCS.. Hope people will give us answer soon!

Postural orthostatic tachycardia syndrome (POTS, also postural tachycardia syndrome) is a condition of dysautonomia,[1] to be more specific orthostatic intolerance, in which a change from the supine position to an upright position causes an abnormally large increase in heart rate, called tachycardia. Several studies show a decrease in cerebral blood flow with systolic and diastolic cerebral blood flow (CBF) velocity decreased 44% and 60%, respectively.[2] People with POTS have problems maintaining homeostasis when changing position, i.e. moving from one chair to another or reaching above their heads. Many patients also experience symptoms when stationary or even while lying down.

Symptoms present in various degrees of severity depending on the patient. POTS can be severely debilitating. Some patients are unable to attend school or work, and especially severe cases can completely incapacitate the patient.
http://en.wikipedia.org/wiki/Postural_orthostatic_tachycardia_syndrome

A vasovagal episode or vasovagal response or vasovagal attack[1] (also called neurocardiogenic syncope) is a malaise mediated by the vagus nerve. When it leads to syncope or "fainting", it is called a vasovagal syncope (vay-zo-VAY-gul SING-cuh-pee), which is the most common type of fainting.[2]

There are different syncope syndromes which all fall under the umbrella of vasovagal syncope. The common element among these conditions is the central mechanism leading to loss of consciousness. The differences among them are in the factors that trigger this mechanism.
http://en.wikipedia.org/wiki/Neurocardiogenic_syncope

Since both of these conditions have to do with the blood flow, I included both for this site. There are a lot of people out there who need answers. We don't have them all, but we can support them, encourage them, and care about them.

Hope this helps.
Pam