Dysfunctional breathing refers to a multi-dimensional condition that is characterised by pathological changes in an individual's breathing. These changes lead to a feeling of breathlessness and include alterations in the biomechanical, psychological and physiological aspects of breathing. This makes dysfunctional breathing a hard condition to diagnose, given the diversity of aspects that contribute to the feeling of breathlessness. The disorder can debilitate individuals without any health problems, but may also be present in those with underlying cardiopulmonary co-morbidities. The ventilatory equivalent for CO₂ (V_eqCO2) is a physiological parameter that can be measured using cardiopulmonary exercise testing. This review will explore how this single measurement can be used to aid the diagnosis of dysfunctional breathing. A background discussion about dysfunctional breathing will allow readers to comprehend its multidimensional aspects. This will then allow readers to understand how V_eqCO2 can be used in the wider diagnosis of dysfunctional breathing. Whilst V_eqCO2 cannot be used as a singular parameter in the diagnosis of dysfunctional breathing, this review supports its use within a broader algorithm to detect physiological abnormalities in patients with dysfunctional breathing. This will allow for more individuals to be accurately diagnosed and appropriately managed.

呼吸功能障碍是指以个体呼吸的病理变化为特征的多维状况。这些变化会导致呼吸困难，包括呼吸的生物力学、心理和生理方面的改变。考虑到导致呼吸困难的方面多种多样，这使得呼吸功能障碍成为一种难以诊断的疾病。这种疾病可以使没有任何健康问题的人变得虚弱，但也可能出现在那些有潜在心肺合并症的人身上。_{CO 2}的通气当量( V _{eqCO 2}) 是可以使用心肺运动测试测量的生理参数。这篇综述将探讨如何使用这种单一测量来帮助诊断呼吸功能障碍。关于呼吸功能障碍的背景讨论将使读者能够理解其多维方面。然后，这将使读者了解如何将V _{eqCO 2}用于更广泛的呼吸功能障碍诊断。同时V _{eqCO 2}不能用作诊断呼吸功能障碍的单一参数，本综述支持在更广泛的算法中使用它来检测呼吸功能障碍患者的生理异常。这将使更多的人得到准确诊断和适当管理。