Systematic Review Exercise, Breathwork and Combined Exercise and Breathwork, Acute Interventions for Stress Reduction in Healthy Adults: A Systematic Review and Meta-Analysis

This review's primary analysis compared the relationship between exercise, breathwork and combined interventions in outcome measures that included any reference to acute stress measurements, as outlined in Table 1. Separate subgroup meta-analyses examined the relationship between intervention duration, categorised as short, medium and long and outcome measures. An additional subgroup meta-analysis was conducted to examine the relationship between low, moderate, vigorous and self-moderated exercise intervention intensity and outcome measures. All meta-analyses were conducted using random-effect models (Borenstein & Rothstein, 1999) on pooled studies to compare standardised mean differences between conditions pre-post exercise, breathwork, combined, and controls to compute an estimate Hedges' g ES, along with 95% confidence intervals (CI) for outcome measures. The Hedges' g threshold was set at 0.2 small, 0.5 medium and 0.8 large, along with 95% CI around the estimated ES (differences between intervention and control groups) (Cohen, 1992). An alpha level of P < 0.05 was used to determine significance. All statistics were analysed using Comprehensive Meta-Analysis (V3, Biostat, Englewood, USA) and presented as Forrest plots (where applicable). Heterogeneity between studies was measured using the I2 statistic (Higgins & Thompson, 2002), and the threshold for cut-off percentage points of 25% (low), 50% (moderate) and 75% (high) was used. The risk of publication bias was tested using Egger's regression significance test and funnel plot symmetry/asymmetry (Egger et al., 1997).