I think that mine is genetic. I have 4 biological siblings and 2 of them, while not officially diagnosed, are convinced that they also have it. My sister had been dealing with what she thought were panic attacks her entire life until she did the poor mans tilt table after I was diagnoses and she turned out to meet the criteria. Since then she has been pounding the sports drinks which has helped her immensely. My brother has really high blood pressure and low testosterone that he was diagnosed with in his late 20s. He also is on a high salt diet and lisonopril (which reduces Angiotensin II). I have another cousin in her early 20s that was passing out from time to time until she was put on a high salt diet. I should probably submit myself and my family to a genetic researcher