Sportopedia Glossary

Autonomic Nervous System

Autonomic Nervous System

The Autonomic Nervous system (ANS) is a part of the peripheral nervous system. It regulates the body’s internal functions and controls processes such as blood pressure and rate of breathing. It consists of three branches: the sympathetic, the parasympathetic, and the enteric. The sympathetic branch has an arousal function and regulates the ‘fight-or-flight’ system by increasing physiological components of arousal (e.g., heart rate) when athletes are faced with a stressful situation. The parasympathetic branch is responsible for ‘rest-and-digest’ activities that include sexual arousal, salivation, lacrimation, urination, digestion, and defecation. The sympathetic system accelerates arousal by releasing the hormones epinephrine and norepinephrine while the parasympathetic system slows arousal by releasing the hormone acetylcholine. The enteric system governs the function of the gastrointestinal tract. Traditionally, the ANS was believed to function automatically, i.e., without a person’s conscious effort.

However, research studies using biofeedback techniques have shown that the voluntary regulation of autonomic processes is possible (Gallucci, 2013). For example, Pusenjak, Grad, Tusak, Leskovsek, and Schwarzlin (2015) found that biofeedback training helped skilled athletes to regulate their galvanic skin response and heart rate after exposure to a variety of stress tests. These results indicate that athletes may be trained to adopt psychophysiological responses that are characteristic of skilled performance.


Gallucci, N. T. (2013). Sport psychology: Performance enhancement, performance inhibition, individuals, and teams. New York: Psychology Press.

Pusenjak, N., Grad, A., Tusak, M., Leskovsek, M., & Schwarzlin, R. (2015). Can biofeedback training of psychophysiological responses enhance athletes’ sport performance? A practitioner’s perspective. The Physician and Sportsmedicine, 43, 287 299.

***Contributed by John Toner & Aidan Moran for Hackfort, D., Schinke, R. J., & Strauss, B. (Eds.). (2019). Dictionary of sport psychology: sport, exercise, and performing arts. Academic Press.