Multiple studies have reported the presence of alterations in the gastrointestinal motility. Pooled data from 352 patients recruited from 6 different studies, showed 21-80% prevalence of nausea, vomiting, and abdominal pain. In four of these studies that measured gastric motility, they found that 43% prevalence of rapid gastric emptying and 20% prevalence of delayed gastric emptying. Furthermore, Al-Shekhlee et al. reported a high prevalence of impaired sudomotor function in the POTS patients who reported GI symptoms suggesting that abnormal post-ganglionic sympathetic function could play a role in the pathophysiology of these GI abnormalities.