Effect of yoga on pain, brain-derived neurotrophic factor, and serotonin in premenopausal women with chronic low back pain.

Background. Serotonin and brain-derived neurotrophic factor (BDNF) are known to be modulators of nociception. However, pain-related connection between yoga and those neuromodulators has not been investigated. Therefore, we aimed to evaluate the effect of yoga on pain, BDNF, and serotonin. Methods. Premenopausal women with chronic low back pain practiced yoga three times a week for 12 weeks. At baseline and after 12 weeks, back pain intensity was measured using visual analogue scale (VAS), and serum BDNF and serotonin levels were evaluated. Additionally, back flexibility and level of depression were assessed. Results. After 12-week yoga, VAS decreased in the yoga group (P < 0.001), whereas it increased (P < 0.05) in the control group. Back flexibility was improved in the yoga group (P < 0.01). Serum BDNF increased in the yoga group (P < 0.01), whereas it tended to decrease in the control group (P = 0.05). Serum serotonin maintained in the yoga group, while it reduced (P < 0.01) in the control group. The depression level maintained in the yoga group, whereas it tended to increase in the control group (P = 0.07). Conclusions. We propose that BDNF may be one of the key factors mediating beneficial effects of yoga on chronic low back pain.