Silence and its effects on the autonomic nervous system: A systematic review

Author: Davide Donelli1, Davide Lazzeroni2, Matteo Rizzato3, Michele Antonelli4
1 Division of Cardiology, Azienda Ospedaliero-Universitaria di Parma, Parma, Italy. Electronic address:
2 Prevention and Rehabilitation Unit, IRCCS Fondazione Don Gnocchi, Parma, Italy.
3 "Humandive", Pordenone, Italy.
4 Department of Public Health, Reggio Emilia, Italy.
Conference/Journal: Prog Brain Res
Date published: 2023 Sep 21
Other: Volume ID: 280 , Pages: 103-144 , Special Notes: doi: 10.1016/bs.pbr.2023.08.001. , Word Count: 182

This systematic review explores the influence of silence on the autonomic nervous system. The Polyvagal Theory has been used as a reference model to describe the autonomic nervous system by explaining its role in emotional regulation, social engagement, and adaptive physiological responses. PubMed, Scopus, PsycInfo, EMBASE, and Google Scholar were systematically searched up until July 2023 for relevant studies. The literature search yielded 511 results, and 37 studies were eventually included in this review. Silence affects the autonomic nervous system differently based on whether it is inner or outer silence. Inner silence enhances activity of the ventral vagus, favoring social engagement, and reducing sympathetic nervous system activity and physiological stress. Outer silence, conversely, can induce a heightened state of alertness, potentially triggering vagal brake removal and sympathetic nervous system activation, though with training, it can foster inner silence, preventing such activation. The autonomic nervous system response to silence can also be influenced by other factors such as context, familiarity with silence, presence and quality of outer noise, and empathy.

Keywords: Autonomic nervous system; Experience sharing; Polyvagal theory; Silence; Systematic review; Well-being.

PMID: 37714570 DOI: 10.1016/bs.pbr.2023.08.001