Impacto do treinamento respiratório do yoga (pranayama) sobre a ansiedade, afeto, discurso e imagem funcional por ressonância magnética

Abstract

The systematization of Yoga presented in the Yoga Sutras of Patañjali, written around 400 CE, proposes an eight limb yoga system, also known as Ashtanga Yoga (ashta=eight, anga=limb), consisting of eight set of practices. Among them, the breathing practices, known as Pranayama, has been associated with positive effects on stress and anxiety. This thesis explores the impact of Bhastrika Pranayama training on markers of anxiety, affect, speech, and functional magnetic resonance imaging (fMRI) using a randomized controlled trial of two parallel arms. Thirty young healthy adults, naïve to Yoga practices, were recruited and evalu-ated by the State-Trait Anxiety Inventory (STAI), the Positive and Negative Affect Schedule (PANAS), Speech Analysis and fMRI (emotional regulation task, and resting state-fMRI), before and after 4 weeks of training Bhastrika Pranayama or control activities. Results after bhastrika pranayama suggest reduction in both anxiety and negative affect, increased activity in bilateral anterior insula and right anterior cingulate cortex. Correlation analysis between fMRI signal during the emotional regulation protocol and PANAS scale showed that among individuals in pranayama group, individuals who most increased the activity in amygdala, right and left insula were those that less decreased negative affect. rs-fMRI results suggest decreased functional connectivity in the right ventrolateral prefrontal cortex (vlPFC) with right dorsolateral prefrontal cortex (dlPFC) after pranayama. Correlation between rs-fMRI data and PANAS scale showed that among individuals in pranayama group, those who most decreased the connectivity between right anterior insula with right and left vlPFC were the individuals that most decreased negative affect. Speech analysis showed reduction in semantic properties when the word “anxiety” was used as seed. No significant difference was found in speech structures after pranayama. In general, our results suggest that the practice of Bhastrika Pranayama leads to changes in anxiety and affect, which was accompanied by changes in the activity and connectivity of brain structures that participate in processes of emotional regulation.