Constipation following stroke : A brain–gut interaction

Abstract

Recent advances in acute stroke therapies have shifted clinical focus toward the long–term outcomes of stroke survivors. Nonmotor complications, such as constipation, are increasingly recognized as key determinants of post–stroke recovery. This review explores the bidirectional relationship between constipation and stroke, positioning constipation as both a risk factor for stroke and common post–stroke sequela. A nationwide epidemiological study in Japan recently identified constipation as an independent risk factor for cardiovascular diseases, including stroke. We suggest the growing evidence that Valsalva straining during defecation can acutely elevate blood pressure, potentially triggering stroke in the elderly. Conversely, meta–analysis of post–stroke complications report that more than half of stroke survivors experience constipation. In these individuals, gut dysbiosis, decreased physical activity, reduced water consumption collectively prolong gastrointestinal transit time, while damage to cortical regions such as the insular and anterior cingulate areas disrupts central defecation control. These findings emphasize the significance of constipation as a mechanistic link within the “brain-gut axis”. Despite these findings, constipation diagnosis remains largely subjective, relying on patient–reported symptoms rather than objective physiological markers. Future strategies should therefore aim to establish quantitative assessment methods. Promising directions include microbiome–based profiling to identify intestinal aging patterns and application of digital biomarkers using smart–sensing technologies within daily toilet use to monitor stool characteristics and circulatory dynamics during defecation. Moreover, interventions will integrate individualized prebiotics–based nutritional therapy tailored to gut microbiome patterns and utilize novel pharmacotherapies. Together, these approaches may provide a framework for personalized management of constipation in stroke survivors and deepen our understanding of brain–gut interactions in cerebrovascular disease.