The Utility of Heart Rate Variability in Mindfulness Research

Objectives Heart rate variability (HRV) is a physiological marker of health with higher values representing a more efficient autonomic nervous system (ANS), which is responsible for maintaining and regulating the body's organs. Higher HRV is also associated with self-regulation and skills necessary to manage thoughts, emotions, and goals. HRV theoretically overlaps with neurobiological mechanisms associated with mindfulness training, particularly those located in neural regions involved in self-regulation. Due to this association, HRV has become an increasingly utilized biomarker in mindfulness-based intervention (MBI) research. Yet, the utility of HRV in MBI research has not been thoroughly examined nor substantiated. In this scoping review, we aim to determine how HRV has been assessed and analyzed in the MBI literature. We attempt to synthesize relevant findings while highlighting variability in the assessment of HRV across MBI studies. Methods We conducted a search of Google Scholar, PsycINFO, and PubMed databases, which yielded 17 original MBI studies (11 experimental and 6 quasi-experimental) that included HRV assessment. Results Among the more rigorously designed and executed studies, we identified an increase in HRV reactivity (corresponding to adaptive changes of HRV in response to a task/stressor) following implementation of an MBI among non-clinical samples. Conclusions Although review findings support the utility of HRV as an objective biomarker capable of demonstrating MBI effects, more research is needed to address the high variability in methods across studies. We discuss major limitations and offer recommendations for future research utilizing HRV measurement in MBI research trials.