Venous blood samples are obtained for analysis and history detailed by questionnaire. Idiopathic Hypovolemia A family history of Orthostatic Intolerance within immediate family members. All participants are adults. Blood pressure and heart rate are measured lying down and standing at regular intervals. Blood samples are drawn for hormones affecting blood pressure control.
Some studies require tilt table testing and medication administration.
In rare cases, patients have developed skin reactions. Problems and side effects not known, and not expected at this time, could occur. At any time during the study, there is the possibility that the symptoms may not improve or may become worse for a time. Precautions always are taken to minimize this. Patients may not receive any benefit from participating in this study.