Effect of Brief Mindfulness Meditation Interventions on Heart Rate Variability in Adults: A Systematic Review.

Heart Rate Variability (HRV) is considered as an objective assessment of stress, that considerably increased the last decades. The influence of Brief Mindfulness Meditation (BMM) on HRV contains gaps in the literature. This study aims to investigate the influence of BMM on HRV. A systematic search was conducted in four databases (i.e., PubMed NCBI, Cochrane Library, Scopus, and Web of Science). To be included, these studies were required to evaluate HRV before and during or after a BMM intervention. The methodological quality of the included studies was evaluated with the revised Cochrane Risk-of-Bias and the quality of the evidence was assessed with the Grading of Recommendations Assessment, Development and Evaluation. Seven studies met the inclusion criteria. Three studies had within subject design, two studies compared BMM with other relaxation techniques, one study was a controlled trial, and one study was an uncontrolled trial. Three studies, including 120 participants, found that BMM is associated with an increase of Root Mean Square of Successive Differences (RMSSD). Two studies reported an increase of the LF/HF ratio; however, the quality of the evidence was low. Although the large amount of heterogeneity can be seen as the main limitation, the results suggest that RMSSD may increase in the short-term during or after BMM, suggesting that BMM might be a promising psychological intervention to temporally reduce the physiological stress of the population. Future randomised controlled trials, measuring long-term effects of BMM on HRV, need to be conducted.Registration and information: This systematic review was registered on the international Prospective Register of Systematic Reviews (PROSPERO) database (#CRD42022291907). The review protocol can be accessed on the following link: brief mindfulness and heart rate variability .