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.