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.
Alex’s Notes: I previously talked about a study examining the beneficial effects of yoga on managing osteoarthritis in older women. As mentioned previously, yoga is an excellent tool for anyone to improve their flexibility, stability, and mobility, and is comprised of physical postures (asanas), breathing techniques (pranayama), and meditation (dhyana). In the study at hand, the effects of yoga on back pain and flexibility are assessed in premenopausal women with chronic low-back pain. As an added benefit, its effects on depression, serotonin, and brain-derived neurotrophic factor (BDNF) are also evaluated.
But before that, why are the later things assessed? BDNF plays an important role in neuroplasticity of the brain and is known to regulate sensory signals at the spinal level, modulating some aspects of pain in adulthood. Exercise is known to increase BDNF and serotonin, and one study reported that serum BDNF increased with 12 weeks of yoga in persons with depression. Moreover, serotonin has been proposed as one of neuromodulators mediating the effect of yoga.
So the study at hand went off and recruited 43 premenopausal (average age 42-years) women with chronic low-back pain, who were not overweight or obese, were using no pain medications, had no spinal surgery, and were not exercising. These women underwent 12 weeks of a Hatha yoga program performed for 1 hour, 3 times weekly, consisting of a 10-minute warm-up, 40-minutes of progressively more challenging yoga poses, and a 10-minute relaxation and meditation cool-down.
As the authors so elegantly state,
“Subjects in the yoga group demonstrated a significant decrease in back pain intensity measured by VAS and a significant increase in flexibility after 12-week yoga intervention whereas back pain increased over 12 weeks in the control group, indicating yoga-induced improvements in back pain and physical function.”
In terms of the secondary outcomes, serum BDNF significantly increased in the yoga group while had a non-significant trend towards decreasing in the control group, and serotonin was unchanged in the yoga group but was significantly reduced in the non-yoga group. Taken together with the primary findings on back pain, it is likely that the increased pain experienced by the non-yoga women may in part be due to decreasing levels of serotonin. Moreover, it appears that yoga up-regulates serotonin production.
Now if only a study would look at performance or ergogenic benefits of yoga in athletes.