The Effects of Mindfulness and Meditation on Vagally Mediated Heart Rate Variability: A Meta-Analysis

Abstract

Objective: Heart rate variability (HRV) is a marker of autonomic nervous system function associated with both physical and mental health. Many studies have suggested that mindfulness and meditation-based interventions (MBIs) are associated with improvements in HRV, but findings are mixed, and to date, no comprehensive meta-analysis has synthesized results. Methods: Systematic literature searches were conducted using PsycINFO, Embase, Medline, CINAHL, ERIC, and Scopus to identify randomized controlled trials (RCTs) investigating the effects of predominantly seated MBIs on resting-state vagally mediated HRV. Risk of bias was judged using the Cochrane Risk of Bias tool. Results: Nineteen RCTs met the criteria for inclusion in the meta-analysis. Random-effects meta-analysis found that MBIs were not efficacious in increasing vagally mediated resting-state HRV relative to control conditions (Hedges g = 0.38, 95% confidence interval [CI] = −0.014 to 0.77). When removing an outlier (g = 3.22), the effect size was reduced, CI narrowed, and findings remained nonsignificant (g = 0.19, 95% CI = −0.02 to 0.39). High heterogeneity in results (I 2 = 89.12%) could not be explained by a priori-determined moderators including intervention duration, study setting, and control type. Conclusions: There is currently insufficient evidence to indicate that MBIs lead to improvements in vagally mediated HRV over control conditions. Future large, well-designed RCTs with low risk of methodological bias could help add to the current evidence to elucidate any role MBIs might play in impacting HRV.

The effectiveness of a single session of mindfulness-based cognitive training on cardiac vagal control and core symptoms in children and adolescents with attention-deficit/hyperactivity disorder (ADHD): a preliminary randomized controlled trial

“…Our results are consistent with previous research showing that brief mindfulness interventions can enhance HRV [ 32 , 33 ]. The overall effects of the MBI on HRV measures were small, in line with other studies; for a review, see Rådmark et al [ 34 ], although the results in this area are mixed [ 35 ]. Even though the effect size was small, these results are particularly important.…”

Effect of breathwork on stress and mental health: A meta-analysis of randomised-controlled trials

“…Indeed, it has been shown that HRV can be modulated during the practice of meditation 106 . However, a recent meta-analysis on this exact matter found insufficient evidence suggesting mindfulness/meditation led to improvements in vagally mediated HRV, and more well-designed RCTs without high risk of bias are needed to clarify any such contemplative practices’ impact on this physiological metric 107 , along with potential mechanisms related to cortisol.…”

Impact of Meditation–Based Lifestyle Modification on HRV in Outpatients With Mild to Moderate Depression: An Exploratory Study

“…Particularly in the last decade, the field of studies examining the effects of various mind-body-interventions (MBI) on HRV has grown. These involved studies on yoga ( 1 – 3 ) as well as mindfulness and other meditative interventions ( 4 – 8 ).…”

“…Regarding the influence of yoga on HRV, some positive effects were found in systematic reviews and meta-analyses, but with the limitation of an overall insufficient study quality and partly contradictory results ( 1 , 3 ). A recent meta-analysis on mindfulness and meditation concluded that there is currently insufficient evidence to indicate that MBIs lead to improvements in HRV over control conditions ( 8 ). Still, MBIs are increasingly used in the treatment of depression and HRV has been suggested as an indicator of success ( 27 ) or predictor of the outcome in depression treatment ( 28 ).…”