Vasovagal Syncope (simple postural faint) is the most common cause of acute loss of
consciousness. Postural tachycardia syndrome(POTS) is the most common chronic form of
postural lightheadedness. Together they afflict many Americans, mostly young women, who are
prevented from gainful employ or school attendance. The underlying mechanism is not known.
Our past work suggests that a simple molecule, nitric oxide, acts to subvert normal blood
flow controls causing blood to pool in the gut when standing. Our proposal will show the
mechanism behind this problem and will indicate effective medical treatments. Patients will
be compared to healthy control subjects.