Yoga has a greater positive effect on a person's mood and anxiety level than walking and other forms of exercise, which may be due to higher levels of the brain chemical GABA according to an article in The Journal of Alternative and Complementary（补充的） Medicine, a peer-reviewed journal published by Mary Ann Liebert, Inc. The article is available free online. Yoga has been shown to increase the level of gamma-aminobutyric（氨基丁酸） acid, or GABA, a chemical in the brain that helps to regulate nerve activity. GABA activity is reduced in people with mood and anxiety disorders, and drugs that increase GABA activity are commonly prescribed to improve mood and decrease anxiety.

Tying all of these observations together, the study by Chris Streeter, MD, from Boston University School of Medicine (Massachusetts) and colleagues demonstrates that increased GABA levels measured after a session of yoga postures（姿势，态度） are associated with improved mood and decreased anxiety. Their findings establish a new link between yoga, higher levels of GABA in the thalamus（丘脑） , and improvements in mood and anxiety based on psychological assessments. The authors suggest that the practice of yoga stimulates specific brain areas, thereby giving rise to changes in endogenous（内生的） antidepressant neurotransmitters such as GABA.

"This is important work that establishes some objective bases for the effects that highly trained practitioners of yoga therapy throughout the world see on a daily basis. What is important now is that these findings are further investigated in long-term studies to establish just how sustainable such changes can be in the search for safe non-drug treatments for depression," says Kim A. Jobst, MA, DM, MRCP, MFHom, DipAc, Editor-in-Chief of The Journal of Alternative and Complementary Medicine.