Research paper by Chris C. Streeter, Theodore H. Whitfield, Liz Owen, et al. The Journal of Alternative and Complementary Medicine. 2010:16:1145-1152. doi:10.1089/acm.2010.0007
A randomized, controlled, 12-week study of healthy adults (age range, 18 to 45 years) showed greater improvements in mood, and greater decreases in anxiety, with a yoga intervention vs a metabolically matched walking intervention. Participants were randomized to receive three 60-minute walking sessions per week or three 60-minute Iyengar yoga sessions per week for 12 weeks. Of the original 52 participants, 34 (19 in the yoga group, 15 in the walking group) completed the study.
The effects of the two interventions on mood and anxiety were measured and analyzed with two psychological scales–the Exercise-Induced Feeling Inventory (EIFI) and the Spielberger State-Trait Anxiety Inventory (STAI)–and by magnetic resonance spectroscopy (MRS) scans to obtain brain gamma-aminobutyric acid (GABA) levels. (GABA is an amino acid that inhibits transmission of nerve impulses in the brain, and GABA system malfunction is associated with higher risk for anxiety and other mood disorders.)
The yoga group demonstrated increased scores, indicating improved mood, in three EIFI subscales: Positive Engagement, Revitalization, and Tranquility. The yoga group had a decreased score in the Physical Exhaustion subscale, indicating decreased exhaustion. The walking group demonstrated an increase in the Revitalization subscale only. The yoga group also showed a decrease in the STAI score, indicating decreased anxiety.
MRI scans of subjects demonstrated that increases in brain GABA levels correlated with improved mood and decreased anxiety. Only in the yoga group, however, did the increase in GABA levels approach significance. The investigators suggested that the effect of the yoga intervention on GABA levels “may be due to the ability of yoga practices to increase parasympathetic nervous system activity.”
Sunflower Photo: Wendy Peragine