The autonomic nervous system and its disorders in young adults

Abstract

The autonomic nervous system (ANS) regulates involuntary functions such as heart rate, blood pressure, respiration, gastrointestinal motility, thermoregulation, and sweating. In young adults, ANS disorders (“dysautonomias”) commonly present with orthostatic intolerance—dizziness, palpitations, presyncope/syncope, fatigue, “brain fog,” and exercise intolerance—often triggered by standing, heat, dehydration, prolonged sitting/standing, or illness.