RESUMO
This ‘discussion paper’ raises ‘provocative questions’ to identify physiological systems underlying vatadosha and candidate biomarkers for vata activity. We explained the strong correlations between survivaland homeostatic functions of the parasympathetic vagus nerve, and functions governed by the five majorsub-types of vata dosha (Praana, Udana, Vyaana, Samaana, and Apana). Four reasons were provided tohypothesize 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 thevagus. Third, the similar roles of vata dosha and vagus in maintaining gut homeostasis, suggest that vagalactivity in the ‘gut-brain’ link is a candidate biomarker of pakwashaya (lower gut), a primary regulatorysite for vata dosha. Fourth, the vagus is the only vital nerve whose activity can be reliably measured andmanipulated. Indeed, vagal nerve stimulation is a USA-FDA approved therapy for certain ailmentsattributed to impaired vata dosha. No other nerve or dosha, has such multi-functional and life-sustainingproperties. These arguments position vagal activity as a suitable candidate biomarker for certain functions of vata dosha.© 2019 The Authors. Published by Elsevier B.V. on behalf of Institute of Transdisciplinary Health Sciencesand Technology and World Ayurveda Foundation. This is an open access article under the CC BY-NC-NDlicense (http://creativecommons.org/licenses/by-nc-nd/4.0/).