The ANS is made up of two branches: the Sympathetic Nervous System (SNS) and the Parasympathetic Nervous System (PNS). The SNS controls the more active “fight or flight” responses such as increasing heart rate and blood pressure.1,2 The PNS can be thought of as the “rest and digest” part of the autonomic nervous system, as it slows down the heart rate and aides in digestion.1,3,4 The endocrine and metabolic systems are involved as well.3 These systems are in balance in a healthy person, and react correctly to outside stimuli, such as temperature, stress, and gravity. When they are out of balance and do not function properly for any number of reasons, autonomic dysfunction – or dysautonomia – occurs. People living with various forms of dysautonomia have trouble regulating these systems, which can result in symptoms such as lightheadedness, fainting, unstable blood pressure, tachycardia or bradycardia, gastoparesis and more.


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