Cluster Randomized Controlled Trial of a Standard Versus Postures-Only Yoga Session: Potential Self-Regulatory and Neurophysiological Mechanisms of an Ancient Practice.

Abstract

It is well-recognized that maintaining a regular yogic practice is associated with numerous physical and psychological health benefits. However, few studies have explored the possible psychological and neurophysiological mediators through which the component parts of yoga-ethics, breath regulation, postures, and meditation-work to produce salutary effects. To address this gap, we conducted a cluster randomized trial to test the following set of theory-based mechanisms: emotion regulation for ethics, self-control for breath regulation, discomfort and distress tolerance for postures, and mindfulness for meditation. We also explored yoga's effects on the autonomic nervous system by examining salivary acetylcholinesterase levels. Participants (N = 260) were randomly assigned in clusters (n = 37) to a single, hour-long standard or postures-only yoga class. Findings suggest that a single yoga class may confer both psychological and neurophysiological benefits, yet there were few differences between the two types of yoga classes. Pre- to post-session main effects of time, all in the expected direction, emerged for five of eight theoretical mediators, as well as for salivary acetylcholinesterase levels. Time X condition interactions observed for three of the mediators-cognitive reappraisal, discomfort tolerance, and expressive suppression-along with findings from the exploratory mediation analysis suggest potential unique benefits of the two yoga sessions for certain outcomes. Additional studies are needed to replicate these results and to test other potential mediators and/or primary outcomes through which yoga might work to promote health.