Can the vagus nerve serve as biomarker for vata dosha activity?

This ‘discussion paper’ raises ‘provocative questions’ to identify physiological systems underlying vata dosha and candidate biomarkers for vata activity. We explained the strong correlations between survival and homeostatic functions of the parasympathetic vagus nerve, and functions governed by the five major sub-types of vata dosha (Praana, Udana, Vyaana, Samaana, and Apana). Four reasons were provided to hypothesize that vagal activity is a reliable candidate biomarker of important vata dosha functions. First, normal vata dosha and the vagus maintain neural, respiratory, and digestive homeostasis, and dysfunctions in both entities cause very similar diseases. Second, vata dosha regulates higher neural functions such as mental health and behaviour, and the ‘polyvagal theory’ proposes similar functions for the vagus. Third, the similar roles of vata dosha and vagus in maintaining gut homeostasis, suggest that vagal activity in the ‘gut-brain’ link is a candidate biomarker of pakwashaya (lower gut), a primary regulatory site for vata dosha. Fourth, the vagus is the only vital nerve whose activity can be reliably measured and manipulated. Indeed, vagal nerve stimulation is a USA-FDA approved therapy for certain ailments attributed to impaired vata dosha. No other nerve or dosha, has such multi-functional and life-sustaining properties. These arguments position vagal activity as a suitable candidate biomarker for certain functions of vata dosha.