Postural orthostatic tachycardia syndrome Come join our Group! Anyone dealing with Fatigue, low blood pressure, orthostatic intolerance heart rate increase visual snow dizziness lightheadedness fainting shaking head rushes or closing vision upon standing, anxiety, poor mental stamina, pain, chest pain, shortness of breath, exercise intolerance, excessive thirst, numbness/tingling/cold extremities, disorientation, tinnitus, headaches, dysapnea, sleep disorders, irritable bowel, temperature regu