LOS ANGELES — Yoga has many proven health benefits, but does it stand up to other forms of exercise? Researchers pitted it against a walking routine and found that those who practiced yoga showed greater improvements in mood and anxiety.Researchers randomly assigned 19 people to an Iyengar yoga program and 15 to a metabolically matched regular walking regimen.Both groups took part in the programs for an hour three times a week for 12 weeks. Study participants were tested several times to measure mood and anxiety. They were also given magnetic resonance spectroscopy scans to measure levels of the brain chemical gamma-Aminobutyric acid, a neurotransmitter that quiets brain activity, reducing anxiety and producing a state of calm. The scans were done at the beginning and end of the study and immediately following a yoga or walking session.Those in the yoga group saw better changes in mood and less anxiety than those in the walking group. The yoga group also saw increases in GABA levels linked with improvements in mood.The study was published recently in the Journal of Alternative and Complementary Medicine.