This purpose of this study was to examine brain GABA (gamma-aminobutyric, the brain's primary inhibitory neurotransmitter) levels in two groups, established yoga practitioners (YP) and comparison subjects (CS), in order to test the hypothesis that brain GABA levels would increase after a 60-minute session of yoga asanas (postures).

Participants consisted of 22 men and women aged 18-45 years. Yoga Practitioners needed to report having practiced yoga for at least 2 days per week for at least 4 months. Comparison subjects had no previous history of yoga practice.

All subjects participated in a baseline and follow-up magnetic resonance spectroscopic imaging scan that took approximately 60 minutes. Subjects then participated in a 60-minute intervention, consisting of the practice of yoga or reading. The YP group was instructed to modify their usual practice to a 60-minute time period that focused on the yoga postures. All sessions were observed by research staff with yoga training. The CS group read for a 60 minute period. Reading material consisted of periodicals and books of popular fiction; content relating to self-help or spirituality was excluded.

Mean GABA levels increased by 27% for the yoga group. The difference in GABA change values between the two groups was significant.

This study demonstrated that for established yoga practitioners, a 60-minute yoga asana session is associated with an increase in GABA levels. This suggests that yoga may be explored as a treatment or adjunctive treatment for disorders associated with low GABA states such as mood and anxiety disorders and epilepsy.