Effects of yoga interventions on fatigue: a meta-analysis.

Background. Researchers aimed at systematically reviewing and meta-analyzing the effectiveness of yoga interventions for fatigue. Methods. PubMed/Medline was searched until January 2012 for controlled clinical studies. Two reviewers independently extracted the data. The methodological quality of the studies was assessed. A meta-analysis was performed. Results. Nineteen clinical studies (total n = 948) were included in this review. Investigated yoga styles included Hatha, Iyengar, Asanas, Patanjali, Sahaja, and Tibetan yoga. Participants were suffering from cancer, multiple sclerosis, dialysis, chronic pancreatitis, fibromyalgia, asthma, or were healthy. Yoga had a small positive effect on fatigue (SMD = 0.27, 59% CI = 0.23-0.31). Seven studies received 4 points on the Jadad score. There were baseline differences in at least 5 studies. Conclusion. Overall, the effects of yoga interventions on fatigue were only small, particularly in cancer patients. Although yoga is generally a safe therapeutic intervention and effective to attenuate other health-related symptoms, this meta-analysis was not able to define the powerful effect of yoga on patients suffering from fatigue. Treatment effects of yoga could be improved in well-designed future studies. According to the GRADE recommendations assessing the overall quality of evidence, there is a moderate effect of the confidence placed in the estimates of the effects discussed here.