The Glymphatic System and Diaphragmatic Dysfunction in Patients with Chronic Obstructive Pulmonary Disease and Chronic Heart Failure: The Importance of Inspiratory Rehabilitation Training

Chronic obstructive pulmonary disease (COPD) and chronic heart failure (CHF) are pathologies that impact mortality and morbidity worldwide. These chronic diseases have multiple causes, and they share some common clinical symptoms, such as diaphragm dysfunction (DD) and cognitive decline (CD), which, in turn, increase the mortality and morbidity rates in patients with COPD and CHF. One of the causes of CD is impaired glymphatic system function, with an accumulation of proteins and metabolites in the central nervous system. The glymphatic system is a structure that has not yet been widely considered by researchers and clinicians. Three key factors stimulate the ongoing physiological function of the glymphatic system: autonomic balance, heart rate, and, most importantly, the diaphragm. All these factors are altered in patients with COPD and CHF. This article reviews the relationship between the importance of the diaphragm, the glymphatic system, and CD, focusing on inspiratory rehabilitation training (IMT). Based on the data reported in this narrative review, we can strongly speculate that a consistent regimen of IMT in patients can improve cognitive status, reducing the cascade of symptoms that follow the diagnosis of CD. Further research is needed to understand whether targeting the glymphatic system with IMT is an effective option for helping patients delay the onset of CD.