The Effect of Slow-Paced Breathing on Cardiovascular and Emotion Functions: A Meta-Analysis and Systematic Review

Abstract

Objectives: Slow-paced breathing entails voluntarily controlling one’s breathing rate to a frequency close to the oscillation frequency of the cardiovascular system. Accumulating evidence indicates slow-paced breathing improves cardiovascular and emotion functions. However, there is no meta-analysis that quantifies pooled effect of slow-paced breathing across studies with nonclinical populations. Method: In this meta-analysis and systematic review, we synthesized the findings of 31 studies (total n = 1133) which investigated the effect of slow-paced breathing on cardiovascular and emotion measures. PsycINFO, PubMed, Web of Science, and PsycARTICLES electronic databases were searched up to August 1, 2023. Random-effect modelling was conducted to compute pooled effect size across studies. Results: Slow-paced breathing showed significant immediate effects in reducing systolic blood pressure (Standardized Mean Difference or SMD = -0.45, 95% CI = [-0.86, -0.04], p < 0.01), increasing time-domain heart rate variability (the root-mean-square-of-successive-differences-between-normal-heartbeats, or RMSSD, SMD = 0.37, 95% CI = [0.16, 0.58], p < 0.01; Standard Deviation of NN Intervals, or SDNN, SMD = 0.77, 95% CI = [0.26, 1.28], p < 0.01), and decreasing heart rate (SMD = -0.10, 95% CI = [-0.19, -0.01], p < 0.05). The effect in reducing negative emotion, particularly perceived stress, was marginal (SMD = -0.51, 95% CI = [-1.06, 0.03], p = 0.06). Limited evidence indicated persistent reduction of blood pressure 3 months post-intervention among prehypertensive samples. Preliminary analysis showed moderate association of the physiological and emotion effects of slow-paced breathing. Conclusions: Slow-paced breathing demonstrated reliable effects in inducing short-term improvements in cardiovascular functions, and modest effect in reducing negative emotions, but its long-term efficacy in improving cardiovascular functions remains to be established. Future studies should continue to investigate the interrelations among the multifaceted effects of slow-paced breathing. Preregistration: This review was preregistered on PROSPERO (Ref No: CRD42023450175).