Transcendental meditation for lowering blood pressure: An overview of systematic reviews and meta-analyses

Background: Transcendental meditation (TM) is a stress reduction technique that can potentially lower blood pressure (BP) safely. The American Heart Association recommends that TM may be considered in clinical practice. Objective: To provide an overview of all systematic reviews and meta-analyses of TM on BP for evidence-informed clinical decision making. Method: Systematic searches of PubMed, EBSCOhost, Cochrane Library, Web of Science, Embase, and PsycINFO for all systematic reviews and/or meta-analyses of randomized controlled trials (RCTs) with TM as an intervention, and outcome measures include systolic BP (SBP) and diastolic BP (DBP). Qualitative and quantitative data were synthesized. The methodological quality of the selected reviews was assessed using the AMSTAR checklist. Results: Eight systematic reviews and meta-analyses are included. Among them is an Agency for Healthcare Research and Quality report, a Cochrane systematic review, 4 independent reviews, and 2 reviews from a TM related institution. The quality of most of the included reviews is fair with a mean score of 5.75/11 on the AMSTAR scale. Overall, there exists a clear trend of increasing evidence over the years supporting the efficacy of TM in lowering BP. However, some conflicting findings remain across reviews and potential risk of bias exists in many of the RCTs included in these reviews. Conclusion: Practising TM may potentially reduce the SBP by similar to 4 mm Hg and DBP by similar to 2 mm Hg. Such effect is comparable with other lifestyle interventions such as weight-loss diet and exercise. Further evidence from long-term well-designed RCTs conducted by independent researchers is needed.