The Autonomic nervous system (ANS) regulates physiological processes, such as blood pressure, heart rate, body temperature, digestion, metabolism, fluid, electrolyte balance, sweating, urination, defecation, and sexual response. Regulation occurs without conscious control, i.e., autonomously. The ANS has two major divisions: the sympathetic and parasympathetic systems. Many organs are controlled primarily by the sympathetic or parasympathetic system, although they may receive input from both; occasionally, functions are reciprocal (e.g., sympathetic intake increases heart rate; parasympathetic decreases it).

 

The Sympathetic nervous system is catabolic and activates fight-or-flight responses. Thus, sympathetic output increases heart rate and contractility, bronchodilation, hepatic glycogenolysis and glucose release, BMR (basal metabolism rate), and muscular strength; it also causes sweaty palms. In addition, more minor immediately-life-preserving functions (e.g., digestion, renal filtration) are decreased.

 

The parasympathetic nervous system is anabolic; it conserves and restores. As a result, gastrointestinal secretions and motility (including evacuation) are stimulated, heart rate is slowed, and blood pressure decreases.

 

Disorders of the ANS can affect any system of the body, originate in the peripheral or central nervous system, and may be primary or secondary to other disorders. Symptoms suggesting autonomic dysfunction include orthostatic hypotension, heat intolerance, nausea, constipation, urinary retention or incontinence, nocturia, impotence, and dry mucous membranes. If a patient has symptoms suggesting autonomic dysfunction, cardiovagal, adrenergic, and sudomotor tests are usually done to help determine the severity and distribution of the dysfunction.

 

Autonomic Regulation is the body's ability to maintain homeostasis (stability and balance) during internal and external stimuli. Autonomic Regulation is always functioning, and we are often unaware of the crucial tasks. When the nerves that control Autonomic Regulation are damaged, Autonomic Dysfunction can develop. Autonomic Dysfunction can be temporary or chronic. Diabetes and Parkinson's disease are two examples of chronic conditions that can lead to Autonomic Dysfunction. BodyComp-Plus ANS-Pro Diagnostic tests Autonomic Regulation through a combination of Heart Rate Variability (HRV) Assessment and Cardiac Autonomic Reflex Tests (CARTs).

 

Cardiovagal innervation testing evaluates heart rate response to deep breathing and the Valsalva maneuver via an electrocardiogram rhythm strip. If the ANS is intact, the heart rate varies with these maneuvers; the Valsalva ratio of longest to shortest HR should be 1.4 or greater.

 

Vasomotor adrenergic innervation testing evaluates the response of beat-to-beat blood pressure to the head-up tilt and Valsalva maneuver. The head-up tilt shifts blood to dependent parts, causing reflex responses. The Valsalva maneuver increases intrathoracic pressure and reduces venous return, causing blood pressure changes and reflex vasoconstriction. In both tests, the response pattern is an adrenergic function index.

​