Baroreceptor reflex sensitivity in orthostatic intolerance

Abstract

Baroreceptor reflex is a negative feedback mechanism that buffers short-term blood pressure fluctuations caused by daily activities such as postural changes and exercise, maintaining blood pressure at a steady level. In autonomic disorders with orthostatic hypotension, including multiple system atrophy, Parkinson's disease, and pure autonomic failure, studies have reported a correlation between the severity of autonomic dysfunction and decreased baroreceptor reflex sensitivity (BRS). However, in postural tachycardia syndrome (POTS), a common form of orthostatic intolerance, research findings on BRS have been inconsistent. The pathophysiology of POTS remains incompletely understood, with multiple mechanisms likely overlapping in individual cases. This review examines the significance of BRS in POTS patients, integrating recent literature with our own clinical experiences. We explore the relationship between BRS and hemodynamic parameters during orthostatic stress, its association with neurohumoral factors, and its potential role in symptom manifestation. Through integral synthesis of current knowledge, including our clinical observations we aim to provide insights into the complex interplay between baroreceptor function and POTS pathophysiology, and to identify directions for future research in this field.