The autonomic nervous system governs many automatic or involuntary bodily functions, including heart rate, blood pressure, body temperature (via sweating and shivering), eye movement and focusing, digestion, and urinary function. Dysautonomia occurs when involuntary body functions no longer work properly, due to either hypofunction or hyperfunction. The presentation of dysautonomia varies broadly and commonly involves pain, weakness, and orthostatic hypotension.^[1]

Some scientists posit that dysautonomia is too broad of a term to be a useful classification of either a symptom or a condition. Dysautonomia is also sometimes used interchangeably with postural tachycardia syndrome (POTS), although they are not the same.^[2] Dysautonomia is a general description of autonomic nervous system dysfunction, while POTS could be due to a variety of causes, some of which are not necessarily related to the nervous system.^[3]