Neuroautonomic and Hypothalamic–pituitary–adrenal-axis Mechanisms of Yoga in Disorders of Gut–brain Interaction: A Narrative Review

Abstract

Background: Disorders of gut–brain interaction (DGBI), including irritable bowel syndrome (IBS), functional dyspepsia and functional abdominal pain, are highly prevalent and are associated with dysregulated autonomic and hypothalamic–pituitary–adrenal (HPA) axis signalling between the brain and the gut. Yoga combines postures, regulated breathing and meditation, each of which may act on these pathways. We review the human evidence for these mechanisms. Methods: PubMed/MEDLINE was searched to August 2026 for human clinical, physiological and mechanistic studies, systematic reviews and meta-analyses. Animal and in vitro studies were excluded. Results: Some patients with disorders of gut–brain interaction (DGBI) show reduced vagal activity, lower baroreflex sensitivity and prolonged cortisol responses to psychological stress. Stress-related hormones, particularly corticotropin-releasing hormone, may also influence colonic motility and visceral sensitivity. In patients with irritable bowel syndrome (IBS), yoga has been associated with improved parasympathetic activity. Similarly, a six-week slow-breathing programme increased vagally mediated heart rate variability, raised rectal sensory thresholds and reduced symptom severity in patients with constipation-predominant IBS. Studies in girls with functional abdominal pain have also found that yoga can temporarily reduce evening cortisol levels. However, evidence for the involvement of GABAergic signalling, insular brain activity and inflammatory pathways comes mainly from human studies outside the disorders of gut–brain interaction population. Although clinical trials have reported improvements in symptoms, quality of life and functional disability, recent meta-analyses have found no statistically significant overall effects. The certainty of this evidence remains very low because of small sample sizes, differences between studies and a high risk of bias. Conclusions: Yoga, particularly slow breathing, plausibly improves disorders of gut–brain interaction through vagal, baroreflex and hypothalamic–pituitary–adrenal-axis regulation, but mechanistic and clinical evidence remains preliminary.