Abstract :
Keywords Sighs; Emotions; Regulation; Flexibility Highlights * Sighs have essential regulatory functions. * Sighs may function as psychophysiological resetters. * Sighs may contribute to psychophysiological flexibility. Abstract A sigh is a distinct respiratory behavior with specific psychophysiological roles. In two accompanying reviews we will discuss the physiological and psychological functions of the sigh. The present review will focus on the psychological functions of the sigh. We discuss the regulatory effects of a sigh, and argue how these effects may become maladaptive when sighs occur excessively. The adaptive role of a sigh is discussed in the context of regulation of psychophysiological states. We propose that sighs facilitate transitions from one psychophysiological state to the next, and this way contribute to psychophysiological flexibility, via a hypothesized resetting mechanism. We discuss how a sigh resets respiration, by controlling mechanical and metabolic properties of respiration associated with respiratory symptoms. Next, we elaborate on a sigh resetting emotional states by facilitating emotional transitions. We attempt to explain the adaptive and maladaptive functions of a sigh in the framework of stochastic resonance, in which we propose occasional, spontaneous sighs to be noise contributing to psychophysiological regulation, while excessive sighs result in psychophysiological dysregulation. In this context, we discuss how sighs can contribute to therapeutic interventions, either by increasing sighs to improve regulation in case of a lack of sighing, or by decreasing sighs to restore regulation in case of excessive sighing. Finally, a research agenda on the psychology of sighs is presented. Author Affiliation: (a) Department of Health Sciences, Vrije Universiteit Amsterdam, The Netherlands (b) Health Psychology, KU Leuven, Belgium (c) Center for Integrative Brain Research, Seattle Children's Research Institute, USA (d) Department of Neurological Surgery, Department of Physiology and Biophysics, School of Medicine, University of Washington, USA * Correspondence to: Department of Health Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands. Article History: Received 28 September 2021; Revised 21 June 2022; Accepted 3 July 2022 Byline: Elke Vlemincx [e.vlemincx@vu.nl] (a,b,*), Liza Severs (c,d), Jan-Marino Ramirez (c,d)