Hatha yoga is effective for reducing anxiety, and efficacy increases with increasing number of practice hours, according to a meta-analysis published online May 20 in the Journal of Evidence-Based Medicine.
Stefan G. Hofmann, PhD, from Boston University, and colleagues conducted a meta-analysis of 17 studies to examine the effect of Hatha yoga on anxiety. Data were included for 501 participants who received Hatha yoga and reported anxiety levels before and after yoga.
The researchers found that the pre-post within-group and controlled effect sizes were Hedges' g = 0.44 and 0.61, respectively. There was a positive association for treatment efficacy with the total number of hours practiced.
Yoga was most beneficial for people with elevated levels of anxiety. Study year, gender, presence of a medical disorder, or age did not moderate effect sizes. The quality of studies was relatively low, but the effect was not moderated by risk of study bias.
"Hatha yoga is a promising method for treating anxiety," the authors write. "However, more well-controlled studies are needed to compare the efficacy of Hatha yoga with other more established treatments and to understand its mechanism."