Yoga and Cognition: A Meta-Analysis of Chronic and Acute Effects.

OBJECTIVES To review and synthesize the existing literature on the effects of yoga on cognitive function by determining effect sizes that could serve as a platform to design, calculate statistical power, and implement future studies. METHODS Through electronic databases, we identified acute studies and randomized controlled trials (RCTs) of yoga that reported cognitive outcomes. Inclusion criteria included the following: use of an objective measure of cognition and sufficient data reported to estimate an effect size. The meta-analysis was conducted using Comprehensive Meta-Analysis software. A random-effects model was used to calculate the overall weighted effect sizes, expressed as Hedge g. RESULTS Fifteen RCTs and 7 acute exposure studies examined the effects of yoga on cognition. A moderate effect (g = 0.33, standard error = 0.08, 95% confidence interval = 0.18-0.48, p < .001) of yoga on cognition was observed for RCTs, with the strongest effect for attention and processing speed (g = 0.29, p < .001), followed by executive function (g = 0.27, p = .001) and memory (g = 0.18, p = .051). Acute studies showed a stronger overall effect of yoga on cognition (g = 0.56, standard error = 0.11, 95% confidence interval = 0.33-0.78, p < .001). The effect was strongest for memory (g = 0.78, p < .001), followed by attention and processing speed measures (g = 0.49, p < .001) and executive functions (g = 0.39, p < .003). CONCLUSIONS Yoga practice seems to be associated with moderate improvements in cognitive function. Although the studies are limited by sample size, heterogeneous population characteristics, varied doses of yoga interventions, and a myriad of cognitive tests, these findings warrant rigorous systematic RCTs and well-designed counterbalanced acute studies to comprehensively explore yoga as a means to improve or sustain cognitive abilities across the life span.